Length of the Salvia High

The amount of time that you experience your salvia high will depend on many key factors. It could have a lot to do with your tolerance to the drug, how much you use, how you use it, and how potent it is. There are many other key components which work together to create a rough idea of the amount of time that the salvia high will last for. However, the high from salvia is generally not that long and it is usually around the same amount of time that it lasts no matter how you use it but it can vary slightly.
Smoking Salvia Leaves

If you smoke the salvia leaves the climax of the high will occur for about ten to fifteen minutes and then slowly drift away. The total amount of time that the salvia high will last from smoking salvia leaves would roughly be about half an hour to an hour.

Chewing Salvia Leaves
If you are chewing the salvia leaves then the high will likely take longer to hit a climax and the total length of the high can be a lot longer than it would from smoking the salvia leaves. It would not be a surprise if the salvia high from chewing quid could last a few hours.
In most cases, the high you get from using salvia (via any ingestion method) will only last for about an hour. However, to keep on the safe side you should cap the high length at 3-4 hours. If you need to drive you should wait till at least 4 hours after you use the salvia so you are not even partially impaired.