How often can I use this herbal ointment, and are there any general limits for topical products like this?

For a product intended for situational use after activities like sport or travel, general advice is to use it as needed, but not continuously on the same area every single day for extended periods. A reasonable approach is to apply it for a few consecutive days when you feel the need—for instance, after a strenuous workout or a long drive—then take a break. If using it daily, consider limiting continuous use on a specific muscle group to about 5-7 days before pausing for a day or two to allow your skin a rest from the active ingredients. This is a sensible precaution with any topical product containing essential oils and camphor. Pay attention to your skin; if you notice increased sensitivity, redness, or dryness, discontinue use. It is not a substitute for medical advice if discomfort persists.