How long can chocolate be held at temper? I just got a chocolate melter and have held some tempered pure chocolate (Lindt Excellence 90%) for a day at 33C. 

I intend to make up 3 or 4 truffles, a few times a week. 

What’s occurred to me is I can just keep this chocolate at temper indefinitely, adding 50g at a time as the level gets low. 

The question is, how long will the chocolate last like this? Will the cocoa fat oxidize quickly or will there be some other problem?

I wonder if this were a chocolate factory, whether the chocolate would be kept at temper 24/7 or whether the machine would be periodically emptied and cleaned for some reason.
I am not an expert in tempering, but I think the long standing time at 33˚C can contribute to V crystals reforming as VI (after all, they do this at room temperature over time). If this happened then it would cause the tempered chocolate to thicken and require melting and tempering again.

Will look forward to more answers on this.