I like to actually checkout the branch I'm reviewing and run the code myself to observe if it does what is claimed, that usually takes up at least 10 minutes in

I like to actually checkout the branch I'm reviewing and run the code myself to observe if it does what is claimed, that usually takes up at least 10 minutes in itself, sometimes more. From my experience most of the issues I find are actually from this type of observation rather than actually reading the code and imagining what it does in my head.