When you're painting a room, you're presented with two different surfaces that are painted differently, as well. The walls are broad and flat and usually are painted with a roller. The trim is narrow; you need to use a brush. Not only that, the two surfaces usually receive different colors. Between walls and trim, which one should you paint first?
When to Paint the Trim First
When You're Taping
When You Are Cutting-In
Trim is not only easier to tape off, but it's also easier to follow when cutting in. If you're the type of painter who doesn't bother with tape and prefers to freehand that nice, clean edge, you'll find it's easier to cut in when you can spread out your brush over a nice, broad area (the wall) and use just the edge to cut in along the fine line of the trim.
When the Room Is Under Construction
If work is still being done on the room, or there's a lot of work traffic through the room, you can buy yourself some time by painting the trim first. This leaves the walls for last, when (hopefully) there are fewer things moving in and out that can mark up the new wall paint.
When to Paint the Walls First
When You Want the Room Painted Fast
Sometimes you're just dying to see what the new color looks like, or you truly can't stand to look at that ugly old color for one more day. If it's a coin-toss between painting trim or walls first, do the walls first. Seeing an inkling of the final product just might give you an energy boost to complete the project.
When You're Not Committed to the Wall Color
Wall color has a bigger impact than trim color. If it turns out that you don't like the wall color, there's a good chance you'll change the trim color, too. Thre is no sense in painting both surfaces twice.
When You Have Temporary Help
Walls are faster to paint and require less skill and care than trim-work. Walls are primarily rolled, while the trim is exclusively brushed and can look bad if someone slops the paint on, muddling the details, and leaving permanent brush strokes.
If you're fortunate enough to have help in the form of partners, family, kids, co-workers, take advantage of it. Have a great, big painting party with dropcloths, paint trays, and rollers, then treat everybody to a light dinner. The next weekend, concentrate on all of that detailed trim-work.