many of us are at different points in the journey of watch collecting (most of us are watch sluts owning timepieces of many different brands while some of us only go for certain movements, price range, aesthetics, and other considerations). Affordability, again, also changes over time for individuals. Tier 1,2,3 or 4 is again subjective but there used to be a thread at TZ about such classification (long time back)..taking into consideration history, movements, complications and etc..i'm sure the lines are blurred now with the emergence of independents.
if the thread is for mods to categorize the classification, i would suggest looking at it from pure "movement" or "origins" perspective. We can classify them like German makes (sinn, lange, stowa), italian makes (pam, anonimo, mazzuoli) , swiss makes (too many), japan/asia makes (seagull, seiko)? further sub-divide them into pilot, diver, casual and dress?
just my suggestion...