I think you need a good one in case electricity gets inestable. What do you need to know buying one? Which one do you recommend?
Assuming you mean a power strip like this it doesn’t really matter what you get. There’s no way you’d overload the power strip unless you have a ton of crazy high-end stuff going on (fwiw my setup is a couple mini computers, a couple monitors, and a decent midrange desktop plugged into a single power strip and the whole thing never pulls more than a few amps).
If that is a potential concern, just make sure the one you get is rated for at least the amount of current you expect to pull. Many if not most off-the-shelf strips are rated for at least 10 or 12 amps, and that’s almost always way more than enough.
Technically you’re SUPPOSED to use an uninterrupted power supply for important things like an expensive computer but I just go with brand name power strips. I like Anker so just use two of their power strips in the office for computer and monitors. I’ve had more issues historically with a UPS being bad than a power strip but it is safer to go with a UPS. I heard decent things about the CyberPower UPS units but power strips are fine for me.
APC also has pretty good UPSs from what I’ve seen
Just get any that can carry the current. Which will be any unless you have a super hungry setup. Dealing with instability is the job of the power supplies of the devices, not the cable.