For things like GI lights (warm white, cool white, super brights, ect) I order packs of 100. For common colours I usually order 25-50 depending on the game. For more rarely used bulbs I’ll order a handful of each. Some places will have sampler packs with flashers colour changers and unique bulbs.
Kits are convenient, but you’ll find that you might want to change a couple bulbs here and there. It’s best to order extra.