Generally, I arrive 1½ to 2½ hours prior to the contracted start time to load-in and setup for an event. It depends on a variety of factors. Let's discuss the specifics of your event, and I can tell you exactly how early I'll need to arrive.
In the rare event your venue does not allow ample time for setup and/or teardown, I may need to hire an assistant so that the same amount of set-up work can be accomplished within your venue's timeframes. Should this be necessary, the additional cost for the assistant would be added to your price quote.