Billable hours; like a lawyer you have to keep track of your work in 15 min increments. This unfortunately will be used against you if you rub management the wrong way. Your experience here will depend on your manager and most are very set in their ways and methodologies. The best advice i can offer someone applying is to do research on the group you are applying to. If they have had multiple positions open up for longer than a year stay away. Those people left for a reason and that reason is poor management.