I get about 4000 km out of a chain riding in dusty abrasive conditions and during the winter months on my multi speed bikes, and single speed bikes enjoy about 6000 km of chain life... and sometimes more.

I use KMC and SRAM chain and their respective quick links.

Pinning 8-11 speed chain is not advised as it is easy to screw things up while pinning 5-7 speed chain does not usually cause any issues.