cheeky to ask my mum about her dress sense?

It sounds as if she's depressed to me, I would approach it from this angle, and try to get her some help.

Indeed. I'm now retired from a professional career and spend most of my life in what my Nan would have called 'play clothes'.

When I was at school you had your uniform, one smart outfit and then 'playing out' clothes in which you could climb trees or wrestle your brothers without worrying.

I no longer climb trees, but I spend the majority of my life in leggings and a sweater.

Maybe she finally appreciates comfort.
Let her embrace it. Get her some more clothes, more bright and cheerful but same level of comfort for her b'day if that bothered!

I suspect once I retire I will just wear comfy clothes and have a reduced wardrobe. This is one of the benefits of age and not needing to be stylish and fashionable unless you really can be bothered. I will be leggings and hand knits most of the time.

If you have a close relationship and discuss clothes and fashion then I’d say it’s a bit odd not to mention it. Not to scaremonger but I remember looking after a lady with a huge tumour on her breast that she’d been hiding under lose clothes because she was afraid to get help. I’m quite sure that’s not the issue here but something has changed so have a chat.

If she suddenly just loves those clothes then fine.

What's wrong with a woman choosing comfort over style?
You absolutely should not say anything, she can wear whatever she likes and should be free from judgement from others, most of all her own daughter.

Any other changes? It could be depression based.

Or it could be she doesn’t have any money for any new clothes. I cleared most of my wardrobe out last year as it was negatively effecting my MH. Much easier now. But I can’t afford to replace things very often. Your mum may be the same.

It’s one thing to be comfy on the house in trackies etc but if she’s going out with her mates, whilst she doesn’t want to be uncomfortable it’s nicer if she’s smart like her friends.

Maybe she’s lost her way with style, take her out shopping and offer some ideas.

I’m in my early 6os. I certainly wouldn’t wear uncomfortable clothes or shoes because they looked better these days. But I still love shopping and making an effort to be nicely dressed. So do friends the same age - even if they are not that interested in “ fashion”
Are there any other changes in your mum. Is she looking after her hair/ nails/ personal hygiene. Is she keeping her house clean to her usual standards. Has her personality changed - for eg - has she been more outspoken/ less tactful than usual.
If it’s just the clothes and she is completely her usual self in other ways then there’s maybe not much you can do. If there are other changes it’s more worrying . Dementia doesn’t always start with only memory problems

We spend such a lot of our lives trying to please others and following protocol. There does come a point where you think you just want to be comfortable - to be you.
Leave her be. She's experiencing freedom!

Are the clothes clean? Is she clean?

If the answer to both is yes then I’d leave it.

My mum always wears the same thing and its dementia for her. Hopefully not in your case as your mum is so young.

So dont say anything. Its a minor thing on its own.

If it is really out of character and you are close then say something , she might just be body conscious if she is busty she might feel her boobs look a bit like a "shelf" or she might just be hiding weight.

I would talk to her and see if there is something going on as it’s such a big change. My mum is in her 70’s and always glam. I would be concerned if she started dressing so differently without mentioning anything.

I think you should ask if she's OK. It's not about her not looking as good anymore, it's about not maintaining her previous standards. It's OK if shes decided to be comfortable, but the same outfit all the time, even when dressed up, is quite a change for someone who previously enjoyed clothes.

My Gran was never fashionable to my memory, but was always presentable. When she got so she couldnt deal with zips and buttons, she adopted stretchy knited two pieces. Not what she'd have chosen but a smart comfortable option for her. Even my Dad, who's always been neat in the same handful of outfits worn until they needed replacing, has hated having to switch to joggers since a disability, and will do everything to avoid going out in them.

It's not the clothes themselves that matter, but what's happened for such a change in attitude.

Yes I'd raise it gently as it sounds like there could be more going on.

How about a gentle "Mum, I've noticed you don't wear as many of the gorgeous outfits you used to wear. You're just as beautiful as ever, of course, but I was a bit worried in case you've not been feeling yourself recently?"

I'm in my 70s and I'd totally hate it if my daughter didn't feel she could talk to me about this! I'd expect her to be very gentle mind you until we'd got to the giggling stage (are you telling me my arse looks massive!!) and then she could winkle out what's really going on. We may decide that I have a good reason to dress like that and then I'd get a hug and we'd move on. Please try and broach it with her, she'll soon shut you down if necessary.

I think I’d just ask her why the change in style?

It does sound out of character

Leave it. There's no way to raise it without it being a criticism.

No woman on earth wants a comment on what she is choosing to wear. Whether you are a teenager with someone saying, 'You're NOT leaving the house looking like that' or a middle aged woman hearing, 'You're starting to let yourself go a bit aren't you? You always used to dress so nicely'.