Got a question about chain replacement intervals on lower end drivetrains.

I built a high power mid drive ebike in June. Replaced the chain at 0.75% stretch, maybe 1500 miles. Since it is a heavy bike, heavy rider, big motor that gets ridden hard figure 1500 mile isn't unreasonable. I purposely went with a 1x8 set up so I can use the cheaper (and allegedly stronger) chains, typically KMC z51's.

But during a search for ebike chain life came across a number of people who said to throw out the chain stretch tool and just replace both the chain and the cassette when it starts to skip. Said no point wasting even inexpensive chains to protect only slightly more pricey cassettes. One even suggested buying a stock of 11 and 12 tooth replacement sprockets because those tend to wear out the fastest.

Just bought a stack of 8 speed compatible KMC chains for under $10 each (got some blue ones for $6). Notice most 8 speed cassettes are under $20. Have to admit the idea has merit.

One worry is the front chain ring is specific to the hub motor, is difficult to source and runs $125. It is a wide and narrow so figure less likely to wear due to no shifting?

What do you think, save the chain stretch tool for the pricey 10&11 speed drive trains and ride the cheaper ones?