I always do long takes and almost never do any voice announcing. For one, when you go to edit the file you are increasing your workload because you have to edit out the voice in addition to editing the sfx. Also, if you think about it ... when you drop a rock 5 times, you will see this in the .wav files when you go to edit, so you can name them as you edit them
A long file is better because you only need to import one file into your DAW, instead of 20 or whatever.
The only time I've announced is when the sound is very specific, like an exact type of antique car engine, or a specific type of gun for example
Otherwise, you'll most likely recognize and remember what is was you recorded so don't bother wasting time announcing and stopping and restarting the record button. You can do all the naming and organizing later in the process.