I'm an active grandpa, raising my teenage granddaughter on my own and trying to earn any extra possible.

Any words of wisdom for an old guy?

Proceed cautiously and ensure that you have the day before and the day of the shop available to work on it. Some of the online shops are convenient; you can call a place, ask specific questions, fill out the shop forms, and you are good to go. Just make sure you avoid canceling a shop, as it will negatively impact your score. While it is not impossible to get more shops, they do consider this factor.

Wishing you successful secret shopping endeavors.