I have moved a few times now. We've been very lucky and done well from property over the years. I think the one house that we ought not to have bought was the one prior to this one, we didn't push hard enough and we ought to have done. This was my fault, I was more nervous than DH and we had only just started the business. DH was never really settled, it didn't increase an awful lot in value and of course, as Em says, the moving costs are high.
Plus, as others have suggested and put simply, an 5% increase in property worth 100k is obviously less than a 5% increase on a 500k property. Then, as Life very sensibly points out, the jump is higher when you do move.
You are right Em, our physical moving costs to move here were over 20k (similar property values), we then spend a further 25k making it exactly how we would want (new build but the builder was a small and wonderfully accommodating sort). The latter was our choice but aimed at saving long term, ie fully tiling the bathrooms, 'upspecing' the kitchen. I think the initial spend have made an overall saving overall for us. So I get you wanting to go for your forever home at this stage.
As others have pointed out, quality of life is very important too and should be considered for sure but I think that depends on folks overall character. DH is the sort to want to push on if possible, it's intrinsically him and our previous house made him dissatisfied and a bit unsettled that he should have pushed harder. It's not about material goods or money in the bank, although it might come over this way sometimes, it's about feeling you gave your best in all things. But I can't think of the best way to say that!!!
I'm not saying stuff very well, but I think Em and her DH might feel the same if they decided to stay in the flat for example?
It's a very individual thing for sure though, my DB for example is the polar opposite of DH and that's totally fine too.
Exercise is definitely brilliant for mental health. There's a programme on at the minute on BBC1 that takes folk with serious MH issues and gets them to run the london marathon. It's totally inspiring. And of course you don't need to run a marathon but the physiological benefits of exercise, not to mention the mental release you get are brilliant!