The recording engineer's work is not done after the session is over. The engineer must spend time working on the audio files to clean up unwanted noise in the files and make sure that fades are properly applied to smooth transitions. Back up copies need to be made and even though the engineer doesn't sit there and watch the computer transfer files, the engineer has to wait and check after the transfer is done to make sure that all the files transferred properly.
I'm usually in the studio hours before a session to check on timing issues and pitch correction. Returning to a session after taking some time off allows me to hear the tracks again with fresh ears. This way I'm more likely to catch little mistakes and focus on the recording's blemishes. This also gives me time to focus on ways to approach and produce the recording. I usually take this time to make notes for mixing the tracks. This way I am prepared for mixing as soon as the client arrives at the studio. If any re-tracking is required, will usually start there and then proceed to mixing. It's the little things like this prep work that keep my clients happy and keep them coming back to record more at Shine On Studio.