Do I have to go?

Go with ninathenana's advice it's very sound

I would go, the maid of honour will arrange payment plans of bite sized chunks and you will really enjoy it, its lovely she wants you there it is a honour - I think you will have heaps of fun x

I agree with Jenpax. Explain to your son that you can't afford it but don't want to offend/upset his fiancée.
I was also invited to my daughter-in-law's hen-night. it was a jewellery party followed by an Italian meal. Not too expensive at the time but it's given my a new hobby and cost me a small fortune since!

Be honest say you can't afford but thank her for asking you I think some hen and stag does getting very prices especially mini hols abroad my ds as had to no to a few because he as young family and stag do nearly as much as cheap holiday with them but if couple want expensive does then I am sure they expect some refusals

I agree that to go just for the meal/early part of the evening then go home. Would be a good compromise. I wasnt invited but friends of mine have done that. You could say you need your beauty sleep / dont want to cramp their style/ it isnt your thing or whatever comes to mind, but at least it shows willing and is sociable.

Money aside, I wish I had been invited to my DiLs hen weekend. It never seemed to occur to her that her mother and I would like to go.

I think the whole business of hen nights and stag parties has gone mad. It seems. It is "the done thing" . Weddings are expensive enough these days without spending more.
I did break my rule of declining gracefully when my eldest grandaughter's friends arranged a hen party in one of their back gardens. We had an "afternoon tea" The chief bridesmaid's mother rustled up China cups and saucers, all the girls had made scones and cakes, we all took a little parcel ( a surprise pair of panties each!) the bride- to-be had to guess who they were from - much hilarity! There were fun games including painting a duck each ( her favourite creature). The sun shone and it was lovely. The energetic young went on to a Mexican restaurant but the mums, aunties and grandmums left them to It!

Would it be so awful to go? --I was invited to my future DIL hen weekend on the Isle of Wight - along with my sons Stepmother. We had a great time - i made firm friends with my ex's second wife and everyone was amused to see Mrs one and two there and getting on so well. We ducked out after the meal about 11.0 and left the others to come back a little later. It was GREAT FUN! and I was glad I went as my son and daughter were so pleased the family unit had been strengthened by the visit and my DIL thought we were both great Mum in Laws to be.!

A "part only" idea may be the diplomatic way to go. Maybe followed by a meal out for over 50s before the wedding ?
Can you beg a lift to London or get a cheap coach deal ?
I blame George Clooney for his extravident 3 day wedding in Venice. (Joking....as I loved every minute of it....by seeing photos and videos !!)

Don't worry, I'll write you an Excuse-me note, your gym kit's in the wash, your pencils have been eaten by the dog, all the usual stuff.

If you can possibly afford it I'd say go (yes maybe I'm out of step with the others) for several reasons. You are going to be family and need to get to know her mum and family a lot better than you do now as today family's are much more connected and if they have kids there'll be birthday parties/Christmas/events to share and it'll be less awkward. Especially if you've seen the recent thread on here about DIL seeing their DMs more with DGC than MILs. Also you can attend daytime and withdraw from clubbing in evenings but at least you've "made the effort", which counts for a lot. You are also making family memories which you can all recall and hopefully laugh about later. Plus you might surprise yourself and have fun! You're never too late for new experiences! On a side note I minister say I admire your sons no secrets policy- good basis for a long marriage in my opinion. Anyway hope you say yes!

You never know, hullabaloo, she may be pleased if you don't go. She may have asked to be polite, or because her mum is going she doesn't want to leave you out. I suggest you thank her very much for inviting you but would she be offended if you didn't come. If she seems upset you may have to bite the bullet but, to be honest, I really don't think she will mind.

Having had the experience of going to both my daughters hen nights - I went for the meal but ducked out of the night club jollity. That really is a young persons game. Could you part time it too?

I'd go with Nina's suggestion, too. I just don't drink enough to feel comfortable with a bunch of young merry hens LOL!

However, a trip to London including train fare, accommodation, food etc sounds quite reasonable to me. It's not a cheap place as I go up several times a year for lectures, etc.

It sounds as though they're planning afternoon tea in the hotel. Could you warmly accept the invitation to go to London for this but return home afterwards? It would probably be a fairly expensive way to spend the afternoon but acknowledges your DIL's kindness in including you and saves you worrying about how you'll feel at the evening events.

What's wrong with the present generation that they have to have a hen night with the Mums and Aunties!

Not enough 'friends' to invite? Surely it is an invitation. there was another thread about weddings where the guest has to pay up.
Don't go unless your son pays.

Relationships with DILs are so often of the treading eggshells ilk, that any offer of inclusion must be handled so carefully if you want a lifetime good relationship afterwards. If her mum is going, then I really would think seriously whether a refusal might come back to bite you. But if you get on really well, then asking if you could host a separate lunch for her, her mum and her aunt, so you could wish her well without cramping her style might be one way out. Or a frank 'I am thrilled you invited me, and will always remember that I was included, but would you like to let your hair down without me on this occasion?' I think the offer to help out with costs is a splendid idea!

I would go especially as the other mother is going - unless they were planning to do some crazy activity e.g. male strippers and a pub-crawl, which from what you say is not the case.

If you really can't afford it that's a different matter.

I would only go if there was another oldie who I knew to be as buddy buddy as me. I wasn't invited to DD's but we had a special meet up for lunch with just the 2 of us. That would be an alternative, and you could treat her.

Just say that it's nice to be asked, but no thanks. Maybe a contribution to the kitty and "have a drink on me".

Be up front and thank your DIL for the invite and tell her your sorry but you cant go because you cant afford it.

Its gone mad. One poor (and I mean poor) DD had 32 hen invites in one year. Actually that made it easier to say No to nearly all of them. The expense is ludicrous, and that is before the wedding, wedding present etc. All 3 DDs have arranged hen parties for each other and friends (no mothers or in-laws expected) - all in the UK and all great fun. They rent a large house - out of season this is NOT expensive when shared between 20 or so - they all bring food and drink or get a delivery from on line supermarkets and have a great time, walking on beaches, etc and getting to know all the bride's friends so that at the wedding itself they already know each other. One DD did a bollywood dance lesson too - Judthepud2 - as the bride was marrying an Indian doctor - great fun on the lawn watched by a herd of cows!!!

My daughter in law had a very lovely girlie 'do' for her friends and I was not invited - happily so. I organised my daughter's hen party - a visit to a winery with lunch and a wine-tasting session, which was suitable for all ages and included invitations for all the females in the family. The cost was less than £50 including a coach to collect us and take us home again afterwards.

I went to DD's hen night but just did the restaurant meal and one nightclub then my sister and I went to a wine bar and then went home. I did not go to DIL's hen party but she did arrange a dinner for the mothers and aunts.
I do think that they go overboard with the celebrations and it becomes very expensive.

Agree, it's fine to opt out. One DDIL didn't invite me (or her Mum), the other had a daytime get together and an evening 'do', I and some others opted out of the evening and not a soul objected. DS understood his Mum isn't a party animal. Be brave and say where you are at. nina's suggestion is excellent, hard to object to that.