Barring the few I'd watched as a child, I'd started watching anime, on a regular basis, fairly late, so I try to balance watching relatively newer shows with much older ones (both, those considered must-watch classics and the odd, lesser-known ones).
A Bit About My Lists and Scoring Criteria
-I don't usually drop anything I've started watching, though I think that's more so because I haven't really come across anything bad enough to drop yet.
-I mostly watch relatively short-running series (26 episodes or less).
-I do occasionally change my ratings, depending on how I feel about an anime later.
-Five is the score for average, so I give it to anything I haven't found memorable in any regard.
-I'll give more than five to anything that has either entertained, or otherwise stimulated me, intellectually or emotionally.
-Scores below five are for anything that either frustrated, or bored me.
-Tens go to my most memorable shows. Nothing is perfect, but these are the ones which either came closest, or had me so deeply invested in them that I didn't notice their respective flaws while I was watching, or reading them.
-Ones are for anything I consider disgusting.
-All scores in between, I give on a case-by-case basis.