On my two speed Brompton I changed the chain after 1500 miles and it skipped on the highest geared cog. Changing the 12T cog for a new one fixed the problem.

The only way to prevent wear on the cog it is to make sure you use a chain wear indicator tool and change the chain before it stretches too much and wears the cog.

I now plan to maybe wipe my chain over a little more often to try and keep it cleaner and thus make it wear a little bit slower. There is a balance here and I certainly am not going to spend hours every few months cleaning dirty chains when they only cost around £10. Cogs/sprockets are also pretty cheap. That said any wear on the the larger main ring would be more costly.

Regards

Jerry