Sometimes it is. I work at a dental office and I have seen people get full mouth teeth pulled out and given dentures because the teeth were so badly decayed.
However, these cases are not very common.
Taking care of your teeth is very important because dentures will never feel like your real teeth. GO to the dentist

save up £5k and have them replaced

Hi,
It sure is.
I didn’t look after my teeth whilst living in the Mid-East, so now have a “spare set” which I gum in.
I was too late to do anything about it.
OK, I should of packed up smoking hand made smokes now and then, given up the rum and cokes at the Officers’ mess, avoided dodgy sea water when skiing, and just put myself in a bloomin’ ball of cotton wool.
Great teeth, but I’m in bed.
Heck life is for living, and if a department goes wonky, so be it.
I am here, me teeth are in the bathroom.
Bob

No, unless they have all been pulled and then you have to still brush the gums.

no, of course not. Start with a trip to the dentist. Have X-rays taken, and assess the damage. Then go from there. If you haven’t taken care of your teeth in a long time (or ever) then expect to have some cavities, decay, and maybe even some rotting. Also expect to spend some $$.

They can only get worst if you don’t!

No, definitely not. Some treatment may be required to get them to a healthy condition, but it will cost more money in the long run, the longer problems are left and I have yet to meet a single person who likes having dentures.
Decaying teeth can cause halitosis and so can gum disease, which is socially unacceptable (and very few people will advise that bad breath is present)There are thought to be implications on general health and well being if the bacteria from advanced gum disease enter the bloodstream. Gum disease can be treated and prevented from re occurring with meticulous oral hygiene and the help and support of a good preventative dentist. Team work is key….most of the important work comes fro the owner of the teeth!

It’s only too late when there all gone.