How many competency levels do you actually need?

Four or five levels is the common answer — something like aware, assisted, competent, expert. Some frameworks run to seven. Others use two: competent, or not yet competent. More levels give a clearer development path. They also give assessors more room to disagree, and the middle levels are the hardest to write descriptors for. If you have run a framework for a few years, did you add levels or take them away? And did anyone outside the HSE or training team ever use the distinction between level three and level four?