Cedar/redwood deck -- have to treat/seal?
A couple of alternatives with which you can ignore the maintenance with less penalty:
- Use a wood species called Ipe (ee-pay), also known as Ironwood. It's an exotic Brazilian hardwood that is extremely durable. It's quite attractive and you can forget about the maintenance for a long time, but it's more expensive and, it is so hard and dense, you must use screws - too hard to nail - and you'll wear out sawblades a little faster.
- Use pressure-treated pine for your substructure, and a synthetic decking material for the deck surface. The synthetic decking is also somewhat pricey, but requires no maintenance, and the pressure-treated lumber also has a rather long lifespan without maintenance, especially if you use concrete footers to keep substructure posts away from ground contact.