American English: 1. "I often sleep in late" refers to not being able to get up in the morning. "I often go to sleep late" would refer to nighttime habits. The sentence you used here is is somewhat acceptable in spoken American English, but it is better to use the first sentence I mentioned. 2. "I often stay up late" is another nighttime habit, as is "I often go to bed late".

Stay up late and go to bed late are the same, but when you sleep late it means that you did not wake up early in the morning. ^^ The other two both mean that you don't get into bed until late in the night.