I would never label myself a polyglot, but I “maintain” the languages I have acquired by them being a part of my normal life. I am parts of local communities or have friends that speak each language natively or at least proficiently. We only communicate with each other in that language.
When I am picking up a new hobby, interest or even simply Googling something, I do so not in English unless I cannot find anything in another language, but this almost never happens because at the very least there is something in German.