How often should you apply Osmo oil?

Good day, I'm curious to know about the recommended frequency of applying Osmo oil. Could you please elaborate on how often one should apply it to ensure optimal results? Are there any specific factors, such as the type of wood or the weather conditions, that would influence the frequency of application? Also, is there a need to strip off the old oil before applying a new layer, or can it be applied directly over the existing layer? Thank you for your time and guidance.