It normally makes sense to rent your ski or snowboard, ski or snowboarding boots, ski poles and helmet on your first few ski holidays.
You start off on equipment especial designed for beginners and progress on to ‘stiffer’ skis quite quickly so spending hundreds of pounds on equipment that you’ll quickly out grow does not make sense.
People often buy their own ski boots and helmet after two or three weeks as these are things it’s good to have comfortable and personal to your foot and had shape, but not when you haven’t skied or snowboarded and don’t even know if you’ll really enjoy it or not.
Borrowing a friend’s equipment is also rarely a good idea as it’s very unlikely it’ll be the right size and type for you, better to let the guys in the rental shop fit you with the right equipment for your size and ability.