usually its 2 years if you come outside of Doha. but in some cases like the Engineers, your employer will give you 21 days vacation free. depends on the company too, they can give you 1 month of vacation. then you can decide if you want to come back or not.

Some people come here as visit visa then look for a job directly. if thats the case, you can come home every 6 months or 1 year.

What are you applying for anyway?