Everytime I see people debating this, I find it amusing that they often forget the strongest evidence it's been longer than 1 year: pinkie pie's birthday. Let me explain. Season 1 episode 25, party of one, and season 2 episode 18, a friend in deed both bring this up. Party of one, pretty self explanatory. Now, in a friend in deed, she clearly says her birthday isn't for another 75 days. You can argue that the episode would have to take place before party of one, but if we're going by that logic, 2 more episodes would have to as well: lesson zero and baby cakes. You can argue that it could still be one year without rearranging, but there is a small problem with that as well. That'd mean the amount of time between the series premiere and party of one, added to the time between a friend in deed and the season 4 premiere is about 75 days. I'd say that makes even LESS sense than the whole thing being 1 year. I'm far from being an expert on the series, but from my analysis, 2 years would make the most sense. Hopefully after reading this, it'll make sense to others too.