I am trying to use the Track Changes feature in Excel. When I save a
document where I have turned on Track Changes, it loses the tracking. There
is no evidence that the changes were being tracked when I open the file
again.

I want to be able to review any changes for at least 2 weeks. The Microsoft
Office Assistance help titled "About tracking changes" says "History is kept
only for a set interval" then goes on to say this interval can be changed.

The problem is it does not say where I can view and potentially change that
interval. What do I need to do to use and modify this feature?