Rain Fall

You are stuck on a magical island in the sky, where there is only one of anything that can exist. In order to survive, and not dehydrate, you must drink from the pond that is in the middle of the island, but there is a catch. The time in between rain falls grows every time it rains, and eventually, you will dehydrate faster than the rain will occur. Lucky for you, there is a magical table that is on the island that, when given two items, will either give you a special item, or a clock to speed up the time it takes for it to rain. How long can you survive on this island in the sky?