@rememberatime I have been in my flat for 2 years and plan on staying at least another two years - yet the landlord won't consider any renovations and says I must improve the property myself.
I guess this would depend on what you wanted; full redecoration of the property with Farrow and Ball paint, and a remodelled kitchen - no way. Peeling paint in the bathroom, yes of course.
I have just had exactly this. I popped over to see my tenants who are staying on and they had no complaints about the property. However, I noticed peeling paint in two places (they weren't bothered about it but I thought it looked unsightly) and when pushed, they mentioned a cupboard door was sticking. It was actually sticking so much that I could barely open it!
So I got that sorted for them, no problem at all. But a few years back, tenants told me they would really like the flat decorated in Elephant's Breath (Farrow and Ball) but were prepared to have a Dulux colour mixed up to match! As I had only redecorated the flat 18 months previously, and it was still in good condition, this wasn't something I was prepared to do.
Sometimes it's easier to do big jobs/redecorate between tenancies because there is no tenant to disturb. Some tenants get awkward about providing access (and understandably so - it's their home), or find work people intrusive. Also really big jobs like new kitchen/bathroom can mean the facilities are unusable for several days - some tenants might use this as an excuse to refuse to pay rent, so it can be easier to do it when the property is empty.
If your landlord is refusing to make repairs that are through wear and tear, I think you have a case to ask again. If you are asking for it to be made to your own personal taste, be prepared to do it yourself (and to return it to the presumably neutral colours the landlord has chosen at the end of your tenancy).