Molten speed wax claims longer chain life than any other type of lube, according to their tests. I prefer wax and oil dissolved in naptha, as a home made liquid wax lube. I apply it often, since it's so easy to do. No chain removal required.
Accurately measuring chain wear is something that few people do correctly. Most chain checkers add roller wear to elongation and exaggerate the actual elongation. The roller OD wear can be 20-30 times greater than the pin to bushing wear that causes elongation. Many people toss chains at the exaggerated .5% elongation reading, in order to avoid new-chain skip when the next new chain is installed, so they only get 2-3,000 miles from a chain. If you use cheap chains, that's probably OK.
Measuring elongation properly only requires a precision 12" rule. It is possible, with Campy chains to have severe roller and side plate wear, with very little elongation. The spacing between the rollers needs to be monitored too. I used a Campy chain for 6,000 miles and though it showed little elongation, the roller wear and side plate wear were extreme and it did cause chain skip, when a new chain was installed. I now use chains in groups of three, alternating their use, so each chain can be used longer and there will be no new-chain skip over the life of those chains. You could increase the number of chains in a rotation.