I had an idea to improve the Sandbox Preview instructions, and (sure enough) someone else has also had the same idea :-)

Add Preview instructions and dates to the Sandbox page within Setup so that you can see all your sandboxes, and which are due to preview / when / etc on one screen.  Much easier than copying the instance to another page going back & forth

Please share and vote for https://success.salesforce.com/ideaView?id=0873A0000015BTPQA2 - Credit to @Mike Reynolds for creating the idea.