“Picks were too bendy. I couldn’t feel what was happening as the thing touched the string”: Brian May explains why he uses sixpences instead of picks

Brian May

Every guitarist has their go-to type of guitar pick: some prefer thinner ones for softer sounds, while others opt for heavier plectrums to help facilitate, well, heavier playing. 

This isn’t a science, more of a general rule of thumb. Paul Gilbert, for example, can shred with ultra-thin picks, and has even taken to drilling holes in his picks to help him play even faster.