For the most part valves have issues with either the seal or collecting gunk near the closing mechanism. The older ones - 60s-mid 80s - seem to have a pretty high failure rate with their seals.
I have not run into any specific issues with 90s built homes. But the fact is if one of your valves is having a problem then all/most will. If it is the same valve it will generally last the same. Also some seals don't do well once they are dried out. Meaning if water was shut-off in the house several times for a significant amount of time then this would probably increase the chance for these issues.
You do not need a plumber to replace these. I would simply use compression valves. Cut your current valve out and replace with compression valve. For most valves it is as easy as that. There are two types of compression valves on the market today that will do the trick - sharkbite (or equivalents) which uses a bite seal and these guys do "spin" - and - the compression clamps.
Most plumbers that would do this work for you would probably use one or the other since it is hard to solder lines that are wet. All you need is a cutter, brush, and your shut-offs (non-turn/ball-valve). Whatever you need they make in compression.
The install for sinks, toilets, things like that is -
- Turn off water
- Undo connecting line.
- Cut valve out as close to the valve as you can.
- Use knife to get rid of any loose copper on inside and outside of pipe.
- Thoroughly clean inside and outside of line - this is key with copper and compression fittings.
- Putting valve on - it just slips on. Make sure it is locked in to place. Turn valve off.
- Turn water on to test.
- Reconnect any lines.
About 10-15 minutes per valve. Do one at a time.