Depends on the caliber. For most "standard" rifle cartridges, I work up in 1 to 1/2 grain increments, shooting 5 of each weight. 5 is usually plenty to tell you what kind of accuracy to expect. When I've narrowed it down, I'll shoot 10 shot groups and compare loads. For smaller stuff, I'll work up in .2 or .3 grain increments. You have to be realistic, otherwise you can shoot hundreds of rounds just to find a load. I'm usually more methodical working up an older gun than a brand new one that I'm pretty sure will handle MAX loads, but I always work up from starting loads.