ICOT, thanks for all the detailed info. A few more questions for do-it-yourselfers:
These concern mechanical mounting issues:
1) If I want to install a reading light on the wall over my bed, where is it safe to put the screws? On one hand I have heard you can damage a beam if you screw into it. On the other hand, I don’t know what the walls are made out of. I assume it is sheetrock. Is that strong enough to hold the light without risk it will fall on my head? So is it better to screw into a beam or to davka avoid beams. In older houses, are the walls generally stronger or not?
2) Same question regarding installing a light in the ceiling. Should one put into beam, or avoid beam? What if it is a very heavy chandelier like Oomis’s friend wants her to put in? How do you properly support the weight?
3) Same question if one is installing bookshelf brackets into a wall which may hold heavy books? How do you support the weight?
Thanks again for your expertise.