Both! Both is good ;)

Milk in Assam and other breakfast teas, in most variants of chai masala, and in hojicha, but not in afternoon teas(which to me, include Earl Grey), (other)green or white teas(except white-based chai masala), or oolongs, yellow teas, or puerhs

Have you tried it with Chinese Gyokuro?^^ Or even "real"(Japanese) Gyokuro ;)

Might actually be easier to find at a tea shop, an Asia market might only have sencha - "real" Gyokuro tends to be kind of expensive(and i don't think you'd find Chinese Gyokuro at the Asia market because i think it's made for the western market) XD

Yes, Oolong too, though personally, I mostly prefer it in the autumn - in summer, more greens and whites

Does that mean you put milk in Darjeeling and/or other highland teas? In Earl Grey and its variants, too? Or do you drink those without milk, or don't drink them at all?

I used to log every tea I drank in Steepster. Haven't done that in quite a while though, and I never had a spreadsheet