What many people might not realize is that paint colors are trends that change from year to year. Paint manufacturers analyze trends in color in other sectors and develop new colors to introduce each year. From what I've noticed, the major trends change every 2-3 years. It's very similar to the fashion industry in that way (just a bit slower to change). In fact, paint colors are often influenced by what's happening in fashion.
So, that being said, I'd recommend bold paint colors be reevaluated every several years to be sure they are still current. I watch HGTV a lot, and see the interiors of many houses all over the country that are for sale (on House Hunters). I am always shocked by how many houses put VERY bold paint up a decade ago and never updated it. I see a lot of schemes that were current in the 90s. Leaving those in your house would be like only wearing fashion that was popular in that decade. Crazy - no one would do that (hopefully). The same goes for the colors on walls. If it's something bright and bold (not neutrals) it should be changed at minimum every 5 years to stay current.
Keep current by checking with major paint manufacturers: Benjamin Moore, Dunn-Edwards, Sherwin Williams, etc. All of these companies do a yearly trend report and introduce new colors. You can check their websites for the most current trends. And give them a try! It's a great way to freshen up a space, and is an inexpensive way to make a major impact on a room. Try a trend on an accent wall if you don't want to make a major commitment. You can always paint it back after a few months if you're through with it. It's like a new fashion accessory.
Here are a few links of the most current paint trends:
Here are a couple schemes that I really like (both Dunn Edwards):
