The answers depend upon many factors, including variety. Pubescens can last over a decade, for example. I didn't have good production at all the first year I grew rocotos, but I overwintered them and got more pods this past season. Waiting to see how their third season works out. I have douglahs in their 2nd and 3rd seasons, still producing heavily. However, based on research I've done, some varieties don't produce well after their second season.
I now live in Ohio (previously in Texas and So. Cal., but grew plants other than chiles in those states), and have overwintered at least half a dozen plants for about 3 years now. Note I grow exclusively in pots, due to the short growing season here. My weather is significantly different from yours, so my approach to overwintering may also be different.
You basically have two options. The first is to just keep the plants going. Where I'm at, this means bringing them indoors and treating them like houseplants, which is what I ended up doing this year. The other option is to give them a big pruning and let them go dormant, which is what I did in past years. Either way, my recommended approach is to repot in the Fall, making sure to remove as much of the old soil from the plant as possible before repotting. Why? This helps remove any nasties which may be hiding in the soil. Plus it gives them fresh soil, which they like. When letting them go dormant, I significantly prune both the stems and roots in the process, and remove all the leaves. Then I keep them in a cool room with little natural light, and reduce feeding and watering. I did very severe pruning the first year, only keeping maybe 5-6 growth nodes, but I haven't cut back that severely since.
Note that if you treat them as houseplants, you still need to water at least weekly; some varieties somewhat more often. If you let them go dormant, however, you may only need to water about every other week until new leaves start coming out. Key factors are to pay attention to the plant for signs of wilting, and do keep watering and feeding on a regular basis.
TheChileMan.org has some helpful growing guides, including one on overwintering: http://www.thechileman.org