I have found that it will save drafts for a bit - maybe a day or so’ish. But if I’m taking a long time, or bouncing around to other board pages/devices a lot, it will delete the draft after awhile. Have lost many a good post/thought for taking too long. Not sure technically what the settings are, but that’s how it seems to work for me.
I’ve learned over time that if I’m writing something that’s taking me more than a day or so, to write it somewhere else (ie, a Word doc) then cut/paste here.
I don’t think there is a way to recover drafts, at least to my knowledge, unfortunately.