titration sac help

[bevanweerasinghe]

hi guys,
i have a titration sac tomorrow and i need some help with errors , the teacher said we cant use any human errors and that we have to assume the procedure is followed accurately. Oh and all salts have to be pure and anhydrous and dont react with the atmosphere. one dilemma i have is  timing in my sacs so im doing questions under exam conditions  but roughly how long should i spend on a question ? (currently spending about 2mins.)
inb4 tl;dr D:
thanks in advance.

[Stick]

There's some level of error found in the instruments used.