I only rate films that i’ve either just watched, or seen recently, in accordance with my own personal viewing standards, which are constantly changing. A film i may have given 5/5 10 years ago may only be worth 4 now, or perhaps even less, so i feel it’s important for my ‘judgement’ to reflect whatever evaluative criteria i’m consciously(or unconsciously) applying in the here and now. Otherwise it’s bound to be less accurate.
I also tend to rate according to genre, or to a director’s body of work(if applicable), so a 3/5 for a movie like ‘Little Nicky’ is not comparable to the same mark awarded to films like ‘Homicide’ or ‘The End Of Summer’, just in case you are wondering, which you probably aren’t.
I’m also into all kinds of different genres, but have obvious preferences towards the more ‘artistic’ end of the film spectrum, which i absolutely feel no shame about ;-)
I try to watch as much as possible though.