Depends on the game honestly, most of the games i play i do try to 100% but sometimes i get bored from repeating the same thing a lot of times, but for the most part i return and play them at a later time.
For the most part i don't really care about ratings that much, i tend to see some pictures about the game (gameplay and art style) then download if i liked it.
try the game out for an hour or so then decide if its worth it or not.
one of the first games i have actually completed at the time.
if you like playing games that takes a bit of time and you do like farm like games this game is for you.