How to upgrade an object

Order them from the PC.

More specifically, click on the computer and choose Order...Order Parts. :)

Thanks - if you click on the actual item to be upgraded, it says use the phone. So much for that.

LOL! I found this funny as my stuff is ALWAYS breaking and whenever my Sims repair the broken items they get free parts. Also, sometimes a pile of junk appears after they repair something and they can search for more parts in the pile. So you can order parts (especially plumbing and electronic), but you can also get free parts from repairing your CONTSTANTLY breaking objects.

I've read other posts about items breaking all the time, but only the frig has broken so far. I have noticed a lot of items have the option to salvage for parts.

You can also get parts from the pile of junk after you repair something.