Here's the procedure to never clean your chain
Assuming we're talking road riding, use the following technique for successful ProLink or homebrew lube (1 part motor oil to 3-4 parts odorless mineral spirits) application and use:
1 - wipe the chain, cogs, pulleys, and chainrings clean with a rag.
2 - drip on lube while pedaling (forward is better) so that the chain just starts to drip lube. Aim the lube between the side plates and between the bushings and the side plates.
3 - run through all the gears several times, front and back.
4 - wipe the chain, cogs, pulleys, and chainrings clean with a rag.
5 - repeat 2-4 if the chain was really dirty
If you do this every 300 miles or so, you will not get any significant gunky buildup, and you won't have to clean the chain. However, no lube is "perfect." A brite shiny chain that is clean to the touch but is well lubed and gives long mileage is still not possible. IMO, ProLink is the best compromise.
Ways to make chains last a long time:
1. Keep the chain clean and well-lubed. It's the gunk on the chain that acts as a grinding compound and destroys the chain. I use ProLink, with the standard procedure, every 300-350 miles. This also means a quick re-lube if you get caught in the rain. IME, wax lubes do not meet this requirement.
2. Spin a high cadence. Those who stomp stress the chain far more.
3. Ride in the big ring when you have a choice. Keeping the chain on the larger cogs greatly reduces stress and there is less chain angle in the 53/18 than in the 39/13.
4. Ride in non-dusty regions. The grinding paste that forms on the chain is a combination of lube and dirt. If your local climate is dusty, this problem will be far worse and your chain will wear that much faster.
5. Buy good quality. IME an SRAM 99 series chain lasts about 60% as long as a Campy Record 9. Cassette cogs and chain wheels wear at different rates too, and this influences chain wear.
6. New chain = new cassette cogs. Many will argue for frequent chain replacement to save their cogs, but the cogs still wear, even with a new chain. The partially worn cogs will cause faster chain wear. The math on chain/cassette replacement (for me) looks like this. Campy 9 speed chain, $25, Chorus 9 cassette $60. Total miles, 10K. Cost per 100 miles = $0.85. The math for people who say to replace the chain every 2500 miles to avoid wearing the cogs too fast: DA chain $24, DA cassette, $75. Assuming ZERO cassette wear (bad assumption), cost per 100 miles = $.96.