>>1752158Keep them in a dry place away from sunlight. Also, don't stick them in the same space as your home heating/cooling system, as ozone and other gasses can break down rubber.
>>1752154Cranksets last pretty much forever unless damaged, it's bottom brackets (replace when rough) and chainrings (replace when sharkfin profile appears or when chainsuck occurs with a new chain).
>>1752129Are you over-inflating your tires? To your question though, if you're looking for a pavement tire as I'd guess, I've always been happy with the grip of the GP5000 and earlier versions in the same line.
>>1752101>>1752061Depends on you really - are you able to do all your own work, have the tools already, and able to find parts for cheap? If so it can be cheaper to build your own bike, but if not then the prebuilt will be cheaper all things considered.