here's my 2 cents. 16 year gm dealership tech.
yes GM tells us to inform customers its only necessary to change oil when the oil life moniter tells them to. the system does need to be reset when the oil change is done. it doesnt KNOW the condition of your oil, it assumes it knows the condition based on the algorythum.
all cars/trucks gm produces from 2011 and newer use dexos (semi-synthetic) or mobil one. if your car is older then that, and you use regular oil, then you still need to stick to the 3K/3mo rule. dino oil loses its lubricity as the miles rack up. it wears out. synthetic does not. but it still gets dirty just the same.
oil life monitering systems are a guideline. DO NOT use it as gospel. they created algorythums to calculate the oil life. but sometimes the system gets tricked. they will not let us know what factors are used. or anything for that matter.
there is a campaign out there to reprogram the ecms on 3.6L chevy and cadillac trucks. the new program changes the algorythum so that oil changes are not lasting 18k +miles. which Ive witnesed several times. NOT GOOD. those vehicles came in with either check engine lights cause the chains were stretched/worn or for excessive timing chain noise, especially at startup. the timing chains are not very robust on those motors, and the variable valve timing components are very sensitive to dirty oil. those parts will wear out and get clogged quickly with diry oil. but if you keep the oil full and clean, its a great engine.
another factor here. engines CONSUME oil. if you try to go 15K miles, it will not be full. and will probably be pretty low. GMs spec is <1Qrt/4K miles. thats the upper normal range. but if you drive 12K miles, and it consumes
.5qrt every 4K miles, now its pretty low.
yes good idea to fill oil filter before putting it on. agreed thats the worst part of an oil change for your engine.
'dry starts' have nothing to do with cylinder wear. that part does not use pressurized oil to keep it lubricated. the eng. bearings are the only part that is affected by "dry starts". everything else only needs a film of oil on it. which it will still have after the time it takes to change the oil.
and to wrap up this book, let me end with my recommendation. no more then 7500miles, unless your doin alot of freeway driving. and I think its a good idea to check the oil level and condition after 5-7K miles at the very least. if it looks nasty, change it more frequently.