I sold a scruffy flat and took a financial hit for it. I bought a scruffy house, and got it at a bargain price.
I guess you have to think through how much time and money would be required to do up your place, and whether you are likely to recoup that. I absolutely think it's worth keeping clean and tidy and doing a bit of a cull/ putting some things in storage so that rooms don't look smaller. I'm slightly cynical about the value of repainting etc.
Having said which, the house we bought was ludicrously cheap - well no, it wasn't, but a very good bargain in a very expensive area. I understand why because I nearly turned heel and walked away as soon as I saw the place. Some of the problems couldn't be corrected: on busy road, architecture just basically not beautiful (modernised 30s semi with no original features). But others were easily corrected: in a road of beautifully kept up houses, this one had had the front fence kicked down, the garden was overgrown, there was loads of dead ivy that had been half ripped off, pulling tiles with it, the porch guttering was hanging off at an angle. Inside, it was painted in shades of violent orange and completely filthy. Every room was jammed full of ugly cheap furniture, including a ludicrous number of kids' beds (6 beds for 2 children!). But the house was structurally solid, huge garden, nice views, round the corner from a fantastic school etc. Best of all: lots of space - 5 beds, and all the others we could afford in the area were 3 beds. I'm really glad we looked beyond the cosmetic ghastliness and had a vision of how it would look. I don't think everybody can: my mother and my FIL both entered the house and said they hated it, and we should sell it immediately.
The flat we sold was in a very posh area and it wasn't awful but it was tired. We had redecorated only a couple of years before (F&B tasteful!) and it had nice wooden floors throughout. The bedrooms and living room were big. However, the kitchen and bathroom were definitely tired and needed replacing, and it was hard to reduce the clutter because we had simply outgrown it and had a lot of stuff that could be tidied but couldn't be hidden. In the end we reduced the price and sold to someone who immediately sent in builders to remodel it. He didn't mind how tired it was so long as he got a reduced price, and I think in that market - where buyers expect nothing but the best - that was always going to be the outcome. In another market, buyers wouldn't have minded the kitchen and bathroom and would have been able to live with them for a couple of years.