On Friday, September 7, 2018 at 11:10:08 PM UTC-4, wrote:
My experience bringing power back to idle after glider release in less than 30 seconds and then not adding power all the way to landing has not been a problem. Our previous engine was well over TBO when replaced, with no issues.
Having more sophisticated engine monitoring might help to run lean of peak to save gas.
Keeping your head outside the cockpit may save you more than gas.

What kind of airplane?
Your experience certainly differs from my 40 years of running towplanes.
UH