Because I like to run but hate it after when my feet hurt like mad not because of my running technique but because my soles of my shoes just let all the shock in really get on my nerves and I have been trying to find a way to stop this from happening. I have heard that by buying a good pair of running insoles you can stop this but so many people recommend custom ones. But recently I have been talking to one of my pals who has actually said that this isn't not needed and you can get by just fine by wearing some off the shelf ones BUT only if you buy the right ones and the ones that are made from a material that molds to your feet which will do exactly what custom made insoles do for a lot less of the price. In fact he said that custom insoles are just a waste of money compared to these ones because your feet are always changing shape and position as you run and a set of custom insoles will be in a fixed shape and will not adapt where as some gel ones will adapt to the changing shapes and positions providing the best support and comfort you can possibly get! There are many different things you must look out for when buying a good pair of insoles as their are a lot of people out there who just want your money...I will also advise against buying wool insoles because they are not rigid enough and do not provide support, wool insoles maybe soft but this is exactly why you shouldn't buy them. You really do need to buy good ones if you ask me as they provide good support and will adapt to your foot shape whilst running absorbing pressure and shock along the way.