My editing lecturer told us, but not in depth, to not watch our footage on a shoot on the camera to check how a shot looks as it can interfere with the timecode and then give problems when batch capturing, he advised us to reshoot if we weren't sure how we shot a scene...How serious is this? Does this only apply to watching and then recording, ie watching a shot and then recording straight after, or can one use Index Marks and End Search functions to fix this? Does this also apply to once a shoot is over and you're going to be watching your footage without recording on the tape again until after capturing?

You run the risk of creating gaps in your timecode when you do that -- sections of blank tape between shots. The camera will pick up where the timecode leaves off if you start recording either before or at the the stop point -- but if there's a gap, the camera will read no timecode and start over.

Some people "stripe" their tapes -- record a whole tape of black (lens cap on) so that the whole tape contains timecode all the way through it, and there will be no breaks whatever you do.

That's not really necessary, and puts a generation of wear on the tape (not to mention an extra hour of wear on your heads for every tape). Just be careful not to have timecode breaks, and keep your review to a minimum.

So does it only come into play when I'm going to record again on the same tape? If I know I'm done capturing for the day and am not going to record again before I capture, is it safe to watch?

If I decide I want to watch something I just recorded, I will point the camera at the ground and shoot 5 seconds of feet. I will check it out, then use the end search (VX2100 has one). I will then back it up a couple of seconds. I have not broken a timecode doing that.

Edit - Bonus of doing that... If I am logging and see feet, I make sure I got the clip before it ;)

So does it only come into play when I'm going to record again on the same tape? If I know I'm done capturing for the day and am not going to record again before I capture, is it safe to watch?

Oh, absolutely.

Oh, and unless you are just playing with footage, I do not recommend reusing tapes. It could potentially increase the chance of a drop out AND tape is your cheapest storage of footage you shot. Keep the originals. And with good software and tape labelling, you can relog tapes if you have keep the log files and project files. If I choose, my editor will let me delete the media for a backup, and batch digitize it again at a later date.