Definitely for ESRI grids but also good practise for other datasets. For example if you create a bunch of shapefiles starting with numbers then decide to import them into a geodatabase, you cannot, as geodatabases do not support tables beginning with numbers or contain spaces\weird characters.
So avoid shooting yourself in the foot all the time and employ a strict, simple, naming convention backed up with simple metadata to explain the name if it gets a bit cryptic (which it can if you start generating hundreds of datasets).
If you start geo-processing with crazy names then python/model builder will blow up and cause you a head ache. And they do get crazy, some "expert" consultant was sending me data with commas and superscript 2's in the dataset name...