NMDA antagonist tolerance seems to be rather long lasting, anecdotal reports even suggest it could be permanent - however I wouldn't go that far, as I had an extremely high Ketamine tolerance, but gave it a few months break and it was substantially lowered - then gave it over a year and a half break and I'm now able to get strong effects from very low doses of Methoxetamine, suggesting my NMDA antagonist tolerance is gone, or minimal at best.
I'd give it at least a month or two if you have a high tolerance though, any use before that time will most likely just further your tolerance and increase the length of tolerance break needed.