Totally agree but I like my scope to make sure. My favorite saying to a newer grower is the same as your response. But, that is because most new growers are very impatient. And should always wait. And get a fricking scope. We shall harvest no wine (bud) before it is time.
Any time I read a strain guide and it says to run it 9 weeks...that means 10 and start checking the trichs then to me.