How often should you clean a hamsters cage?

This honestly depends on the hamster and the size cage you have them in if you have a hamster that only goes in certain areas you just have to clean them and if you have a very large cage you don't have to clean it every week. I have male Syrian in a 40 gallon breeder tank and I only have to clean it every 3-4 weeks but I do clean his toys and spot clean about 2 times a week so it really only matters on your cage and you pet

Once a week.

In order to have a healthy hamster, you need to clean the cage every week.