Admittedly, I read manga more than I watch anime. It's something I only started noticing recently.
I don't rate anime in a 'professional' way whatsoever. The rating given solely depends on enjoyment. Some people might say it's biased but I only watch anime (and read manga) for entertainment. If I like the characters, I might just bear with the plot no matter how ridiculous it may be.
I'm a little bit humble so my version of dropping anime is when I lose interest in a certain series, I tend to forget or get lazy in trying to watch the next few episodes.
I usually watch new anime every season. I'm not particularly excited with anime adaptations (from manga or games) if it's something I've already read or played before. A good example is Mirai Nikki and Sankarea. I tried watching the first few episodes but ended up forgetting about it and instead watched the rest of the new anime.