How much free storage should I keep? I have a Huwaei mate 10 lite and it has internal 64 GB, I don't use memory card because I use two sims. 

How much free storage should I keep? Is 10% enough? Or 20%?
Use as much as you need – but keep free as much as possible:


At about 10% you'll start to receive warnings about storage space running low, so you shouldn't go below that.
Plus, the more free space is available, the better the controller can handle wear leveling – which will prolong the life-span of your storage.