Pressure first, always. Underinflation is the leading cause of tire failure on work trucks and trailers, and in desert heat it matters even more. Check pressures on a set schedule with a calibrated gauge, and include duals, since the inside tire of a pair is the one that gets missed.
Tread depth and wear pattern come next. Uneven wear points to alignment, suspension, or inflation problems that will keep eating tires until they're fixed. Catching the pattern early saves the next set.
Look at sidewalls and valve stems. Sun-cracked rubber, bulges, and brittle valve stems are common in the valley and easy to miss during a quick walkaround.
Don't forget the trailers. Trailer tires often sit for long stretches, age out before they wear out, and fail without warning. Check their age as well as their tread. Finally, keep a record. A simple log of pressures, rotations, and replacements per vehicle tells you which trucks are costing you and when to plan the next tire purchase. We can handle all of this on a schedule, right in your yard.