I have a feeling I'm missing something obvious, but the Wild Magic sorcerer's Tides of Chaos feature (PHB, p. 103) states:
Starting at 1st level, you can manipulate the forces of chance and chaos to gain advantage on one attack roll, ability check, or saving throw. Once you do so, you must finish a long rest before you can use this feature again.
Which suggests that this is a once per long rest ability.
But it goes on to say:
Any time before you regain the use of this feature, the DM can have you roll on the Wild Magic Surge table immediately after you cast a sorcerer spell of 1st level or higher. You then regain the use of this feature.
Which seems to suggest that you absolutely can use this more than once per long rest...as long as the DM has you roll on the Surge table after casting a spell of 1st level or higher.
Does that make it so that this feature is only once per long rest if the DM (or general wild magic) doesn't have you roll on the surge table before the end of the long rest? Otherwise, it's as many times as you want as long as you recharge it with a surge roll. Is my understanding correct?