Honestly, I think some clever Kickstarter-savvy person should invent a new way of painting around trim and other exclusionary areas of a room.  This whole business of cutting in vs. applying painter's tape is a flawed exercise.  Other people are waiting for their jetpack; I'm waiting for an easy way to paint around trim.

In the absence of miracles, we are stuck with the old methods that have been around for ages:  painting by hand, otherwise known as "cutting in" or taping up those excluded areas with painter's masking tape.

What Are You Avoiding?

Anything in a room that is not easily removable and which does not get painted, typically:  trim around doors and windows, ceilings, and baseboards.  

You will remove:  sconce lights, thermostat boxes, curtain fixtures, light switch plates, and outlet plates.

What Are These Techniques?

Cutting In:  Favored by professional painters, the cut-in method is pure freehand.  Using a 3-inch sash brush and a special "cut bucket" (a small paint can without a lip), you draw wide sweeps of paint close to but not touching the excluded area.  

Masking:  Low-tack painter's tape removes with no sticky residue and is the only kind of tape you should use.  Apply painter's tape to the excluded area, one edge of the tape right on the dividing line.  Paint lightly on top of the tape.  Remove the tape after the paint has thoroughly dried.

Which Is Best?

On the whole, I recommend using masking tape over cutting in.  The masking tape method loads you up with more work on the front end, but less aggravation and mess on the back end.

 Just make sure that when you apply the tape, you press it firmly down with your fingernail to prevent paint seepage.

As an added benefit, when you use 2" or wider painter's tape, you protect excluded areas from paint rollers, as well.  Two inches is the width of the zone where your paint roller might accidentally touch.

When the non-excluded surface (the area to be painted) is bumpy or anything other than completely flat, your cut-in job is even more difficult.  

Should Do It Yourselfers EVER Cut-In?

As long as the wall is flat, there are some spots where cutting-in will yield results as good as a taping job:

• Short Distances:  Anything that is 3" or less can be cut in relatively cleanly, even by amateur painters.  This is just a quick swipe, and shaky hand-work will not show up.
• Against a Glossy Area:  If the excluded area is glossy and will not stain from the paint pigment, you can slop over into that area and still wipe it clean.  In fact, one technique for painting mullioned windows is to paint the mullion, not even trying to avoid the glass on either side.  Then with a rag, you can wipe the glass clean.  Even if the paint dries, it will peel off with a fingernail or razor.  Sealed hardwood flooring can tolerate some slop, too.  Paint can be removed from vinyl window frames, if allowed to dry into thick puddles or specks.

Forget Cut-In Gimmick Tools

I've never met a paint edger tool that I've liked.  

Paint pads only smear the paint.  Why buy a paint smearer when you're rolling the walls?  The two textures just don't work together.

Fancy, expensive edgers like the Accubrush are better only in that the smear line is thinner than with pads.

In the end, you're better off masking the room and brushing up and onto the tape with a narrow brush loaded with a minimal amount of paint.