I have see a light wing out land in a paddock engine missing , it wouldn't,t miss on ground but off and on in the air . After a lot of time wasted it was found 912 pump failing replace problem fixed .
I have a back up pump fitted always get used for my take off ,then out of circuit I turn it off but at same time watch fuel pressure gauge to check stay in green on manual pump mode .
The idea is to have some common sense in a fuel system in your aircraft , it's not a car or bike or tractor etc , it is a flying machine and has a Big different called risk . I fuel system is most likely to show a problem under full power ( which is lack of full flow ) the first daily check of the pump max flow is taking off . Most aircraft taxi,s down and carry out a fast idle engine system check then apply full power to take off , big down side so not the best time to find out you haven,t got enough flow throw pumps and lines . So you have to reduce risk by having a back up pump in take of up to at least 1000 feet where you might have a better chance having to deal with a problem . If you have ever flown model planes it is a standard practice to hold mode at full power nose in the air for a few minute to check motor doesn't,t stop with a fuel flow problem . It,s a bit hard to hold full size aircraft on the ground with nose in the air or either many pilots tire it up preflight and ground run at full power unless you are on a aircraft carrier .
So those with only one pump fitted to there aircraft they are a test pilot every take off ,because you don,t know you have a lack of full flow problem until you are out of runway .
Weather listed in the 912 manual or not common sense goes along way .