to not want to subsidise my mum's furniture?

How she allocates your rent is up to her OP.

Your post reminds me of those dads who think their CM goes towards hair and nails and want a breakdown of what it's spent on.

Pay towards the bills then she can use her own money to buy what she wants… she’s telling you she needs to start charging you so just agree an amount and stop dictating what she can use it for.

This.

i know it seems unfair.

you have said you understood that being an adult is paying towards you living there which at the time she didn’t need and while she may not actually spend the money on that in your opinion her income for furniture is less because she is paying the bills on her own if you contribute that frees up money that otherwise would not be available for furniture because it went on bills.

so think of it as you are contributing towards the bills and with the spare money she’s saving because you are contributing she’s using to buying furniture.

i mean the best idea all round is you look seriously into moving out as soon as viable but I understand that’s easier said than done.

YABVU
How would you react if your employer decided they would only pay you if they approved of how you would spend your earnings? You are a fully grown adult who earns money while you have been living off of your mum and now she would like you to finally contribute. You don't get to decide how she uses that contribution. If you can't accept that then move out and learn to pay your way (a clue-your future landlord, utility companies , council tax office and supermarkets won't listen to a control freak tenant/customer telling them how to spend the rent/bills/food money).

YABU!
You aren't paying rent. Start paying rent and she can spend it on whatever she wants.

Can't believe this is for real, you sound so entitled! Give your poor mother the money and just be grateful she has housed you for this long!

My 25 yo DD rents a 2 bed place near us. We are in one of the cheapest places in the UK to live, apparently. Here are her rough costs per month.

Rent £730
Council tax £170
Gas/Electric £150
Food £350
Water £70

That's just under £1500 per month. What do you estimate it will cost you to NOT live at home?

YABU, just pay rent and let your Mother buy what she likes.

It's a bit shit of her to say she doesn't want to take money from her daughter, then turn around and say she wants it for luxury items.

That being said, I would work out what you think it costs in utilities and food and then pay that each month. Or just the utilities and you sort your own food. That would be fair and should still leave you with money to save.

YABVU

Agree with other posters that you pay her the fixed amount you r already agree and she can spend it on what she likes

And yes, it is controlling to contribute only by paying for grocery shops.

I really can't understand what your issue with her wanting to decorate her house a certain way is

Start paying rent. You're not subsidising her or her furniture. She can't afford to save or pay for the blinds because she's subsidising YOU!

Just pay sensible rent than get out ASAP.

Is your backdated the rent and food money she could buy the furniture now.

Pay her monthly rent

Yabu. She pays for your food? You don't buy any food or give her money towards it? You should be giving her an agreed amount each week or month. She can spend it how she likes.

You need to pay your way...what she saves on your food shop/puts aside from your rent can be spent on furniture if that's what she wants to spend it on.

Try looking at it from a different angle. Your mum needs money to buy nice furniture. But she can’t buy it because she is paying the mortgage, council tax, electricity, gas, broadband etc. If you pay rent she can then use her money to buy nice things.

Yabu.
You are annoyed because she's referring to the cost as going in furniture but ut doesn't matter. You need to give her a set amount of money per month and then uts up to her how to spend it.
And tbh if your 25 and have thus far never contributed financially, i think its pretty cheeky to quibble over giving her money regardless of what she wants to spend it on

A landlord can spend whatever they want in the rent, it’s not for the tenant to dictate.

You pay rent and she spends it on whatever she likes . I can’t see the problem as you are happy to contribute apparently .

She can spend your rent money on what ever she wants.
She has decided she needs a contribution from you. Pay up or move out.

pay rent, she can then use the money saved by you paying your fair share of bills to buy her furniture or maybe move out NOW and pay your own rent and bills then again she can use money saved by you not being there on the funiture.
in other words, stop being a cocklodging mooch and pay your way!

YABU

I think you just need to pay rent and it’s up to her what she spends it on.

You think she doesn’t need such fancy furniture but it’s what she wants. She can spend her money as she pleases. If you think of it as paying for the stuff you are using you might feel better about it.

You are using food and utilities which do cost and presumably council tax has gone up too. It’s nice she didn’t want you to contribute before. I guess her outgoings have gone up.

Agree with the other posters. You contribute your rent, she spends it however she wishes