Many suggestions and experiences shared here, with all being specific to different requirements. (Shop-like floor vs. home garage use) One very important point to consider prior to rolling up your sleeves or emptying out your bank account, is the moisture level of your concrete. This will determine which application is best and going to last without flaking or weakening of the surface material and regretting your product selection. Place a plastic garbage bag on your floor and weight it down with some books or wood. Lift it the next day and see if moisture has accumulated on the surface beneath the bag. If so, your surface coating will be susceptible to flaking as your garage is not weeped properly around the perimeter and moisture is getting under your slab and wicking upward. Select the appropriate product for this type of condition.
Echo this.
I have done three garage floor over the years, and there are two things that kills epoxy floors:
1. Moisture. I say leave the taped section of plastic (about a square foot) for a few days, up to a week. When you remove it, if there is any moisture the paint will loosen, just a matter of time. There are things )and special prep) you can do but I never had to.
2. Chipping, esp from using a jack) with metallic coaster or wheels. A heavy car on a small surface area like that will crap the paint. You can also see the same effect if you drop a heavy and sharp object, it can also chip the paint. Or use a jack stand without anything below it (use a square piece of MDF, or even a thin piece of sheet metal.
As others have said, a (gloss &) lighter shade of beige or blue works well, reflects light and make garage seem brighter, and makes finding dropped things easy.
Just be careful walking into garage in winter with snow on shoes. Slippery, very slippery.....