There is an interesting technical issue with baseboard on modern construction that I would be willing to bet that most DIYers never thought about, until the installation starts looking like shit, as you're nailing it up. Most material is 3-1/4" tall. most base gets air nailed to the bottom of 1/2" sheetrock, and most sheetrock is installed with the tapered edges run horizontally. Typical instructions call for two #6D finish nails per stud in the flat face of the material to attach it to the rock. If done this way, you will end up with a shit job, as the base will tilt into the rock taper and leave a big, ugly gap at the top. Professional trimmers that I hire, do it differently. they place the material on the proper spacer blocks (if it gets carpet), locate the studs, then toe-nail the base to the studs. They use one #8D nail per stud. It is placed high up on the base, typically in the decorative routing at the top (the ogee of the bed mold if you're a real geek about this) This technique allows the material to suck tight to the wall, and stay tight, ABOVE the tapered rock edge. This technique involves a great deal of downward pressure on the gun as you pin the base tightly to the wall. Frequently you have to take a wonderbar, and pry a bit of upward pressure on the bottom of the board to free up your spacer blocks, to remove them. Now IMHO, it's absolutely impossible to do this on soft carpet and pad, and get a top quality job. Obviously, I haven't tried, just as I wouldn't listen to somebody advocating the installation of the interior doors before the sheetrock goes up. Naturally, if you are installing taller base, like 5-1/4" or 1" x 6" stock, you have enough wall contact above the taper, and you can face nail the material without issue.
Another issue is deciding you are going to paint a project. I use a few painters that have some mind blowing skill. Like being able to cut a dead straight line in, for 15-20 feet, without stopping, and doing it a few hundred times per house. They use a whole set of techniques that are honed over years of practice, and I doubt that I would ever master. A new home interior goes like this.
The house is rocked, taped, spackled, and finish sanded.
The tiled floor areas are covered with a layer of red rosin paper, stapled down, edges taped with duct tape.
Except for tiled areas, ALL trim and doors are fully installed.
They caulk the edges of all trim, tight to the sheetrock.
After properly taping off and covering windows, and removing the interior doors, they spray and roll the paint on the walls. At this pointed the trim already had a factory coat of primer, and the paint they use (Sherwin-Williams) is listed as a suitable primer and top coat for walls and trim. After clean-up, they them hand paint all the trim and cut in all the edges where the trim meets the sheetrock. I then do the tile work and install the missing trim, tight over the tile. The doors are spray painted and reinstalled. The carpet is installed last, and there is no additional trim used to cover any gaps in any flooring. The work is so nice that I have had another paint contractor accuse me of lying about the price, and the fact that the trim was all hand painted as a last step. The entire interior is seemless, without a visible joint anywhere. This may be an unusual process in many areas of the country, but I'm a few hours out of NYC, and it is apparently the old school way of doing the work, from back in the day when most painters were Greek, and many never bothered to learn English. The interesting part is that is can be extremely fast and efficient.
I guess it truely is whatever works for you, and however it's done in your local area. But there is a method to my madness, and I'll put the work of my guys up against anybody, at any price bracket of new construction. Good luck.