Wow, some of this makes me feel reeeeeeal old. Originally, blackstriping a tape was almost a necessity because everyone was using linear editing systems and they weren't very frame accurate even at the highest level of gear. Tape stretch was often the problem. Now the only good reason for blackstriping is because you may have the habit of popping the tape out or playing it and not going back into your last footage causing a time code break. I suppose another good reason would be because you intend to shoot over everything that is already on the tape. I always, should I look at my footage mid tape, going back into the last few seconds or use the stop edit button. If you go back into your tape, it creates a good habit and that is to waste a few seconds shooting at the end of his clip. It will give you more room to play with in and out points as well.
I have always been in the habit of not mixing tapes though there have been occasions where I've done so without problems. However, old habits die hard and I generally do not mix. I knew about the lube problem but wasn't aware that had been corrected.
As far as tape breakdown, if there is going to be tape drop outs they will generally be in the first and last 30 seconds to a minute of the tape. These parts of the tape get the most stretch and abuse when winding and rewinding. But that's okay since I have found it to be a good practice to waste the first minute with color bars, black or just wasted tape before I go in the water or shoot anything I may want. Tapes do last a lot longer than they used to, however, it is still advised to store tapes in places not too hot nor cold and to store them standing up with the rewound tape on the bottom, not to lay tape cases flat onto each other. Its a matter of gravity.
Steve B)