It is important you are well aware of where shooting will be taking place and you should know this with enough time to adjust things according to the location. The location may influence things that go as deep as the script.
The location essentially sets the needs for lighting, props, audio, and much more. If you are not prepared for the intricacies of your location your production will suffer.
You should be comfortable and prepare a shooting plan that deals with all potential issues regarding your location. Scouting is basically done to not only pick the best location, but best filming time. By scouting the place out you get a feel for the traffic as well as pedestrian traffic because this can be influential to your decision, you get a look at lighting and how the sun affects contrast on your location, this is especially true for exterior scenes.
The locations commodities, will you have all you need within one place, is it a studio setting, will you have changing stations and hair & makeup accessible.
One thing to be mindful of is the space. Is it an open space or crammed, depending on this you may have to adjust your camera movements to accomedate the space your working with or choose a completely new location.
Interior lighting, are there windows? Is it a small room that creates bounce light, will you have to paint walls to offset bounce, all things you have to prepare for.
The big take away here is scouting strengthens your production because it allows you enough time to adjust to the weaknesses of the location.