If you want to give this the full nerdy treatment, we don't know how many days are in some of those undefined intervals, so the timing is uncertain. Jeph has said "more than six months and less than ten years". People who are my masters at obsessing with detail have tried to extrapolate the passage of time by measuring hair growth.
Yeah, I just went through the series noting changes of clothing and characters greeting each other with 'Good morning!'. I know, it' s pathetic.
It's interesting, though, that Jeph is pretty good with continuity. If Marten is wearing a blue t-shirt in the morning, it's on him all day. You'll even see a tiny patch of blue under his jacket when
he's outdoors. It's also notable that the characters change clothes every day. Most cartoon characters keep the same clothing forever.
I think I'll go count the hairs on my head now.