Reflective glass chips exterior paint, 1950s style art deco. Looking for link on how to recreate that and where to purchase chips?

We painted our living room hallway walls with semi-gloss paint. After completion, we didn’t like the color. Looked nothing like the chart showed it would be. I’ve been told that to repaint, we have to sand off the paint, otherwise the new paint won’t stick. Is this true – or

I primed my bathroom ceiling and it looks just fine. Is there any problem with just stopping there?

We have a new concrete block wall that was built to seal off an entrance to the building. Without doing some homework, it was painted with a regular exterior water based semi-gloss paint. Now we are having problems with the water seeping through the wall once in a while when

Can I paint water based enamel over water based acrylic paint?

I have an exterior door to paint which is a different color on the interior side. What are the correct colors to use to paint the edges of the door?

I have to paint the walls and trim in a house and they think the trim is painted with oil but not sure. Is there any way to test it?