When I first started I had no temp probes. Did have a clock though, those things are everywhere! I kinda knew how long it should take. (give or take a few hours). Started there. Even today I just have a regular old therm (dial version, slow...) I only use it right at the end to make sure my feel and eyes are in agreement with the tempature it is.
I do think they can be useful tools, but they can be used as a crutch as well. It is all about balance. I have watched alot of your videos, and I still have alot to learn, but hey, thats majority of the fun.
You only fail if you do not try.