I don't mind honestly! I know some stuff (like grass or stars especially) is really tedious to do over and over again. I especially understand with direct front views, cause making both sides symmetrical is exceedingly difficult. Like someone else said though, it's best just to do it on the sketch layer and line it separately, cause that allows for minute changes that just make it look more natural in the end
I typically don't mind, but it's really impressive if they don't! If I'm having trouble replicating something like an eye (which is seldom), I tend to copy it in the sketch phase and then draw them individually with the line art
as long as it isnt destractingly obvious? like if you are drawing a lot of roses and you wanna repeat them. its ok to repeat a clutster of 6-10 you drew from scratch, but if its just one flower pasted again and again it becomes really jarring. I think as long as it doesnt stand out to you right away and you gotta look close for it then its cool. theres laziness then theres efficiency.