Boat rental or buy a tour in milos

Hi folks, I’m going to Milos in the second fortnight of May and I’m looking things to do.

One of the MUST activities is to spend half day in a boat but I’m no sure which is the best option: 1- rent a boat and drive around by my own (i don’t have any experience) 2- buy a boat tour.

I’m not fully fan of tours since you can’t manage the time you want, but also I believe it is more expensive and I don’t not the risk of being inexperience