Being you started it that many times a day the engine was always warm. Maybe the plugs didn't even get cycled during those times. Just saying.I ran my July 2010 built truck 145,000 miles before trading it off for a 2015. I started my truck 10-14 times per day So my glow plugs got cycled a lot.
Never had any problem with them.
I've talked to the guy who bought my truck, don't know how many miles he has put on it in 8 months, but he has not had any glow plug problems.