I always build on carpet, barefoot laid out all over the place. Like was said before, use common sense when it comes to static and you'll be fine. Most of the parts can withstand a static shock to most of the component, HOWEVER, there is a small chance that a static shock will hit the right part of the wrong component and damage it. It only takes a small zap, but to the right spot, deadly. And we're talking on the milivolt scale, way less than would arc. With PCBs try to touch the sides, not the top/bottom, parts like PSU and heatsink/fans are for the most part all right with some zap. SSDs pretty safe from zap, HDDs slightly less than SSDs, the big areas of worry are CPU/GPU and Motherboard, thems the ones to be extra careful with, but ya, been building computers for almost 20 years now and never, not once fried anything with static. No static strap, on carpet, every time, 10 - 12 times a year, 20 years. Be cognizant, but don't let it ruin your day.