In reply to wbo:
Bit of everything. Mainly because it's another thing to add to the 'to do list'
What I've done with walking and climbing boots is buy them instore or online and just try them out, no problems so far.
But when long distances or speed are involved, small problems become bigger ones before you know it, friend of mine recently bought new trail shoes instore for walking the Camino but had to bail out half way due to injury. Turns out they needed a specific type of shoe for their foot shape something or other.
Maybe I should just suck it up, and strap on my £25 bottom-of-the-range New Balance trainers from the Sports Direct sale next time I'm in the hills, and see if I end up a cripple.