All of the trim in our recently purchased home is oil based.

I would prime

Clean, rince, sand and prim is best. The apartment I lived in came in with latex over oil and started peeling like a bad sunburn because they did not etch the paint. Your hardware store should be able to tell you what to do.

You don't need to prime. The oil based paint makes an excellent primer. You do need to sand well. Anywhere that you don't will be subject to the paint peeling, as Julie said. Spend more time sanding and cleaning than you do painting.

use citristrip to remove the exsisiting paint.

It is best to scuff ( sand) it then prime with acrylic latex then paint.

After cleaning them thoroughly an oil based primer will cover it well and then, I believe, you could paint over with an acrylic paint.

I would sand it down, which I know is tedious and time consuming but it will save you time and hassle later. I know “they” say you can prime and paint latex over oil but I have also seen bad results later on when it starts peeling.

If you just absolutely don’t have time to sand the woodwork, you could always install new trim and prime/paint it

or

If you just really want to keep your trim and paint it too- Your best chance for success is to:

Clean all of your trim well with TSP. Make sure to rinse well even though it says you don’t have to. Then use a deglosser like ‘NoSand’ and get it in every nook and cranny. Use wood filler to repair all damage to your trim. Then Prime your trim with a good quality primer before painting.

😊

Sand it, TSP, then a good primer, then paint.

https://www.todayshomeowner.com/video/how-to-paint-over-oil-based-paint-with-latex/

http://www.diynetwork.com/how-to/rooms-and-spaces/doors-and-windows/how-to-apply-latex-over-oil-based-paint

Latex paint can be applied over oil-based paint. There is nothing inherent in the oiled-based paint material that precludes an additional latex layer.

The surface must be properly prepared. Glossy surfaces will not take a second layer of paint well.

Preparation includes deep clean, sanding, and dry cleaning with a tack cloth.

Use a primer before putting down the latex. While advisable for most painting projects, it is a requirement for this one.

Oil-based paint cannot be applied over latex paint.

If you have multiple layers (five or more) of oil-based paint, consider scraping off the paint first.

When you can do this on exteriors, interior use is more forgiving than exterior use.

Yes. Use Zinsser Bullseye 123 primer first and then paint with your latex paint.

Thank-you to all for the advice!