A friend of mine from up north found that he really enjoyed using the turbo assist (the highest level of assist) on his CREO Specialized e-bike. Doing that, he found that he was in the smallest cog in his cassette far more frequently than when he used to ride his mechanical bike. He learned from the local bike shop that e-bike owners with similar behavior were replacing about 3 cassettes for every chain replacement. On his mechanical bike he could get the cassette to last for 5 chain replacements. He realized that the wear on his CREO cassette is because 1) he likes to go fast and 2) his single chainring is only 44T (vs. the 50/34T set up he had on his mechanical bike) resulting in his greater use of the smallest cog on his cassette. Since that smallest cog has only 11 teeth, all the wear was focused on a small area.
In further discussion with the bike shop, he learned that the small cog is replaceable and cheap and available through Nashbar for less than $10 – far less than replacing the entire cassette.
So, if you notice skipping when you power forward in the top gear, it may not be the chain, but a $10 cog instead. My friend subsequently reported that he was easily able to manage changing out the smallest cog himself.