The new stuff doesn't impose any new maintenance requirements, and functions as well or better that the stuff that cam before. Yes, more speeds means narrower chains, and therefore shorter chain and sprocket life, but otherwise it's no different.

Whether you find that added gearing options is worth the extra dough or not depends on where you live and how you ride. If you live in the plains or along the east coast and ride in flat to lightly rolling terrain 7s or 8s is fine. OTOH if you ride long distances on the road, and/or live in very hilly areas, you'll appreciate every added gearing option.

In any case saying "I'll stick with 8s" is fine, but you may not have any choice in the matter. Eventually parts wear out and top quality 8s is no longer being made. I'm currently riding 7s freewheels on my commuter, and concerned about my future options. Some time soon my rear rim will wear through, and I'll need to decide whether to rebuild on the same hubs, or do an unnecessary and expensive "upgrade" to cassette system with 8s or 9s.