That seems abit excessive. You should log in and get onto the timetable page 10-15 minutes before opening, then refresh as it gets closer to the opening time. I found that this works effectively. The other day when I didnt do this, I couldnt even get onto the site, it was "Full". Although Im sure it also depends on what coruse your doing and the demand - I thought Accounting for me would be packed but luckily it hasnt been.