When it comes to the ratings I give games I try not to rate anything that I've not played at least three times. Yes, there are exceptions. Some times you can tell something is wonderful or plain God awful with one play (and in the God awful category, sometimes not even a full play.)
When it comes to recorded number of plays, I started in mid-2008. And starting in February 2013, I started recording games I played with my then 3-year-old son. Just to get a better feel for things I've done in the past pre-BGG, anything recorded as Jan 1 1975 is something I have at least a vague recollection of playing in the 70s, Jan 1 1985 in the 80s, and so on for 95 and 05. Those plays are conservative guesses.