How many times is it permissible to perform tayammum when water is unavailable or there is fear of illness?

If water is unavailable or its use is difficult, Tayammum (dry ablution) is permissible. Tayammum is valid for a believer for up to ten years if they do not find water. When water is available, the believer must use it. If water is found after performing Tayammum, water must be used. The person who has performed Tayammum may pray as many obligatory and supererogatory prayers as they wish with their Tayammum, as long as they do not invalidate their ablution or become able to use water.