In my humble opinion, there is nothing worse than billing time. Just think of the feeling you get when you’ve spent a day doing a million random tasks in your sad beige office, and you have no ten-minute entries to account for that day (i.e., you get no credit for a day spent at work doing work things). Not only is billing a pain, the practice of accounting for your time is even worse. While I was no better at it when I was at my Biglaw firm than at the small firm, the former had some software that would send me mean emails if I did not get my hours in on time. Oh, and there were scarier partners that would come after if me if I had a delinquent time report.
At the small firm, on the other hand, I was instructed to fill out time entries by hand, give them to my assistant to type into a billing program, review the print-out of the hours inputted by my assistant, and then send them off to the partner to review and approve.
I was less efficient at billing at the small firm than at my Biglaw firm. Not only did I lose precious ten-minute increments working with my assistant to bill hours, but I also worked on a minimum of four matters, and switching between matters meant less efficiency. And I suppose there are other things people do at small firms that they cannot bill for — like go get business or something?