Question bout spotting (etiquette? )

[~AK49~]

Question isnt directed towards being a spotter, but asking a spotter. Ill try to make this short lol. Today i was doing some skullcrushers, and a guy said he would spot me and had me get 10lbs heavier (70's ez bar). Did four sets, first set i could bust out 5-7 reps before he had to help some to get to 10. Second set was the same, the last few reps were harder for me tho and he had to work harder. Last two sets, i could only get 4-5 reps, before he was REALLY helping out lol. Last set last 3-5 reps were basically all him lmao. All in all, it was a great workout andmy triceps are jello right now. Thinking about doing it again next time, hence my etiquette question. I know with heavy exercises such as bench and whatnot you shouldnt have your spotter do all the hard work, but what about lighter exercises?

[msagrain]

You only need a spotter for bench and mind muscle concentration over weight.