Could anyone please help with these questions I have related to restore points in WIndows 8.1 please...

1) What exactly does the 'Show more restore points' check box do?
This is found from control panel > recovery > open sytem restore > choose a different restore point >next.
I thought it might hide older restore points, but this doesn't seem to be the case.
When I check this, only one additional restore point appears (of type 'backup') and it is not the oldest one.
I don't get the point of this setting. Why not just show all restore points all the time?

2) Does anyone have a link to a site which describes what the different restore point types are please (I'm seeing these types - manual, backup, system, install, critical update)?

3) Why would you need to configure system restore to work on non-system drives?
When you click control panel > recovery > configure system restore, under the 'Protection settings' area, you can select different drives and then when you click 'configure' it allows you to switch on/off system protection and set the disk space usage for non-system drives. I'm a bit confused as to why you'd want/need to do this for non-system drives?
In my case my system drive is the C: drive and teh other two drives contain nothing other than data. Maybe if I had installed application on these drives then this this would be when I'd need to turn on system protection here?

4) How often are restore points automatically created by default and is it possible to adjust this to make them more frequent? (I appreciate that you can create these manually, but I'd prefere to automate if possible)

Many thanks for any help!