I don’t know how the rest of you think about this, but I have my miniatures divided up conceptually into “projects”, which is my term for a batch of miniatures that “go” together. This is usually a combination of period (e.g., Late Bronze Age, Hundred Years War, Renaissance, Fantasy) to include various IPs (e.g. Buck Rogers, Burrows and Badgers) and scale (e.g. 1/72, small 25mm, heroic 25/28/30/32mm, 40mm). For each project, I usually have a baseline rules set that I am using or planning to use. Some projects have multiple sets of rules. Usually figures are based consistently, but projects intended to support multiple different styles of rules sometimes end up with a mix of basing. My old school 25mm fantasy is probably the worst offender in this category, with a mix of 60mm squares with 4-8 foot figures for mass battles, individually mounted vintage figures generally on 25mm wooden bases with flexible steel underlayers, and figures mounted on steel washers (generally 1” or 0.75”). I have 60mm square magnetic movement bases to allow the individuals to be grouped for easier participation in mass battle games.