I prefer the "look" of side splashes...others don't. If the vanity is granite a precise fit can be had but if it is off...rather than tweaking the slab the wall often gets modified...then it becomes necessary to patch or cover that.

You don't have to have them by any means but they do tend to give it that "finished" look as well as conceal any spaces where the granite doesn't meet the wall perfectly. With the vanity being wall-locked, I would encourage you to go with the sidesplashes.

It will definitely give it that finished look! I dont think it looks that good just going straight to the wall. Its hard to describe it better than "it looks finished." i will see if i have some before and after photos to show you how the back splash and side splash make such a big difference. Here is a picture with a vanity we did that had the back & side splash.

I would have them as it looks more finished, without looks like a mistake.

Agree with all here ... I classify it as a must if the top is 37" or smaller

Another option would be to tile the walls around the vanity after the counter goes in. Basically, anything that will close any gaps between the wall and counter, not that the counter is not cut precisely, but walls are not always plumb.

If you are going to put a backsplash (tile or another surface) on the entire side and back walls, I say no. It is my opinion that it is a much cleaner look if you have a slab of granite with back splash above. If not... def use a back/side splash.

You want them...even with minimal use, the walls will get splashed and stained up without them...unless you are planning to run tile down the side walls?