I strip the factory lube off so I can start with my home made paraffin based liquid lube that will be used for the life of the chain. It yields excellent chain life and doesn't attract dirt. Not all chains show a lot of elongation as they wear. Campy chains and the new sram axs chains can be extremely worn at the rollers and side clearance between the links, with little elongation. Measuring the roller spacing between the outer plates on two adjacent links can show extreme wear, with little elongation. Users think it's great to get 6,000 miles or more from a chain, until they install a new chain and get new-chain skip, meaning the cassette is worn out. I have a length of scrap tape measure with a permanent pin through the 10 inch mark that allows for full length measurement of elongation.

I alternate the use of at least 4 chains on each cassette so I'll never get new-chain skip. I'm alternating 10 chains on my two axs bikes.