A very good summary of BestPractices about Perfomance optimization of a PowerApp. These things are usually only “learned” when you have already implemented some apps and especially only when there are larger data sets and performance is important. Variables are a great help, but also OnAppStart in combination with Concurrent. It is important to note that if you want to perform multiple Concurrent functions one at a time, when queries reference each other. z.B. -> A category list is first queried and then a different list is asked for.
You can see this video here on my blog because I have rated this video with 5 stars in my Youtube video library. This video was automatically posted using PowerAutomate.