You should never make 100% of your lifts in any session. If you do it tells you one thing, you are training too LIGHT!!! Many people talk endlessly about the evils of too many missed, and there is no doubt lots and lots of misses are a bad thing. But making all of your lifts is probably even worse. That means that you haven’t even had the guts put the weight on the bar.
Putting 100 kg on the bar is the absolutely necessary first step in snatching 100 kg. Have the courage to load the weight. Of weights that you do load on the bar, my belief is that you should make about 85% of those lifts. I have put this number between 70% and 95% at various different times, when I was in various different moods. But 85% is a good middle ground. If you usually make too many more than this, you may be training too light. If you make too many less than this you may be training too heavy and not developing good motor patterns as quickly as you could be. This applies mostly to singles and doubles, but when using an RM of 3 or 5 reps, when do you call it quits? I don’t think there is a hard and fast rule. BUT, if you are doing a 5RM and rep number 5 is picture perfect and your name is not Caleb Ward, you are training too light. Form breaks down with heavy weight. And for a normal humans it is impossible to be moving picture perfect on the last rep of a 5RM. Period. On the other hand, if rep number 1 is dangerously bad, take weight off the bar. Most 5RM’s will break down between rep 2 and 4 to some extent.
But every weightlifter should remember that the whole point of weightlifting is to lift the most weight. So if you are going to err, err on the side of GOING FOR IT! Don’t fail for lack of trying.