You can make as many restore points (automatic or manual) as you like. The shadowstorage (that's where the restore points are being kept) is a FiFo (first in, first out) storage area. So the size of the shadowstorage will determine how many recent ones will be kept..
Figure between 250MB and 1GB per restore point. Usually 15% of your C partition would be an appropriate amount of shadowstorage. But if your C partition is very big (like close to 1GB) a lesser amount will suffice.
You can also create restore points on data partitions. That is handy to retrieve lost files with Shadow Explorer
. But if your data resides on the C partition (which is a very bad practice), Shadow Explorer can also retrieve lost user and system files from there.