I have also gotten conflicting advice, similar to what you have heard. I'm no expert, but I'll tell you what I ended up doing which seemed to work out pretty well, at least so far. We bought a ~100 year old home six months ago that we're just getting around to painting now, after rewiring. Most of the trim is painted with what seems to be a high gloss oil-based paint, and a much of it (especially doors and baseboards) is quite dirty. The only trim I've painted over so far is a few doors, but I'll be starting on the rest of the trim in a couple weeks. For the doors, I scraped off just whatever bits were already flaking off, then washed them really well, and then used "liquid sandpaper". If your trim is glossy you may want to use liquid sandpaper to remove the gloss. It's not a paint stripper, so you won't be left with messy globs of dissolved paint. It just removes some of the sheen so that the new layers bond to it better. Then I primed with an oil-based primer. I have used both latex and oil primers in a previous home, and the oil primers always seem to bond better. Then painted with Regal Select Semi Gloss. I haven't tried Natura, but I might... Anyway, I would recommend liquid sandpaper rather than sanding as long as the old paint is basically well-bonded to the trim, then oil-based primer, than latex paint. I'm curious what suggestions other people have..

If it were me, I would sand well and use the acrylic primer. The reason is that even if I were to use an oil based primer, I would still sand, so what is the point? Do they want to skip the sanding entirely?

Thanks, brushworks! It's a lot of work removing all the paint -- we have tried a whole arsenal of scrapers, blades, drill attachments, and chisels -- and I'd hate to go through all that again. I live in the Pacific Northwest, and unfortunately there appears to be no Muralo dealers within 25 miles. Do you have any experience with Benjamin Moore primers? I like working with them.

Those cabinets were finished with gloss latex applied with a 1" diameter thin nap roller and a 2" angled brush(for cut in) after a coat of BIN primer. The doors were removed(trim was also removed and spray painted brushed nickle from a rattle can) and painted flat. The boxes were painted in place. Several keys to a good paint job. Preparation is the most important. The trim was removed. Everything was washed with water and dish soap solution, rinsed(damp rag) , let dry. A light sanding to knock down the build up from the trim/doors being varnished together and a coat of BIN applied with the 1" diameter roller. Why a 1" diameter roller rather a larger type? Air bubbles. Or rather the absence of air bubbles. Seems counter to do that, but the smaller roller actually is faster. Technique is the next area. Those smaller rollers also minimize roller lines, which show up after the paint is applied. Primer often looks terrible when applied. As long as the coverage is complete, the visual look is unimportant. No roller lines, no blobs, and no bare spots. That is where the technique is important. Wet edges allow the primer(or paint) to mix seamlessly. Starting a row in the middle, ending with rolling form one end to the other. Never start a roll in the field after the initial application. You can end in the field by pulling the roller up off the surface, but starting leaves a mark. In the example of those kitchen cabs, once a door was primed and painted, the door was inspected by looking at an angle(with a light) to insure the surface was completely smooth. By doing that, you can see any imperfections. Good primer and correct primer application makes any paint look better. Don't over roll and especially don't over brush. The more you roll over an area, the more chance something bad will happen. Trust the paint. Good paint will self level to a point. Very shallow brush lines with disappear with good paint. I favor man made brushes. Purdy is my usual. Brushes are designed to hold paint inside the bristles. Overloading a brush lessens the ability of the brush to load and apply the primer/paint. There is usually no need to have more than 2" of paint(end of bristles up) on the brush. Less is more. That is why the technique is so important. Using a roller is usually easier than using a brush because the roller applies more material per pass. With the correct application technique, there is little visual difference between the two ways of applying material. Spraying is an entirely different process. The only similarity is the material is either primer of paint. Everything else is different. Except for the wet edge and over application factors. I do not recommend DIYers try spraying interior finishes. Way too much prep(covering everything(including floors) and a lot of experience with the spraying equipment.