In reply to BattyMilk:
Short answer: boots wear out, just try lots on and buy whatever has the best possible fit.
If you know if you have particularly wide/narrow or high/low volume feet, it's worth mentioning that and people can give particular recommendations.
Long answer:
The bad news is that boots wear out just like everything. In most cases, apart from £500+ B3 mountaineering boots, it's probably not worth worrying about resoling them. It's not cheap to get done and even with good quality leather boots, the uppers and midsole are also likely to be gone by the time the soles are worn out - at least that's my personal experience with the general sort of use you describe.
Cheaper, lighter fabric boots generally last a shorter time than more expensive, heavier leather boots although it's not clear which approach is ultimately better in terms of value for money.
Buying boots on sale is great - but ONLY if they are one of the models you were considering buying anyway.
I go through a pair of traditional Scarpa leather boots every 4-5 years. That's been a couple of pairs of Scarpa Delta and I'm currently on the Scarpa Trek in the low volume version which is probably a better fit.
I've also got a pair of the more modern styled Sportiva Aequilibrium which are a fantastic lightweight and super comfy higher performance mountaineering and scrambling boot. However, the added stiffness that's great off the beaten track means they are not great for pounding tarmac and given the cost of them I'm keeping them for the hills and not the garden or wet walks to the pub.
In general that's your dilemma - stiffer boots offer better scrambling performance but that often comes at the expense of comfort for longer walks on pavement/tarmac.
Anyway, I think the best possible advice is to try on lots and lots of boots. That way you can start to get an idea of what make/models suit your foot shape. That means multiple shops - not just deciding from what's on offer in the first large shop you go to. Unfortunately other than North Wales or the Lake District there's not many places with multiple outdoor shops stocking a wide variety of brands in a small area...
Anyway, hope that's useful!