If you are learning then yeah use a retractable with a helmet, impact vest etc. Gloves are good too save your hands and fingers.
Make sure you have some sort of quick release. When I was learing my leash got wrapped arround a cray pot float and I was strung out like a bungee jumper with no return. After 5 minutes the leash snapped. Then I stopped using the leash.
Then one day thought I'd attach one to a pickle fork. Bad idea came a gutser in surf and the board caught, then the board (ping) sliced my left wetsuit leg half off (I was wearing a helmet for the cold). That killed it for me, no leash learn to body drap, kite with good mates who can help you find your board.
(PS I've kited Vic, QLD, NT, TAS and WA and have always found these people, just a few words hi not from arround here any pointers, bit of respect etc..) gota get to NSW one day, wind dies every time I'm there

.
Anyway more details on attachment ...If you are going to attach it to your board middle of tail is good, never middle of board acts like a sea anchor. Also don't have surf fins on that end use ATacs or nice ones that won't gouge should they hit. Avoid pickle fork style and dove tail boards too. Try dragging the board by leash through water and see what happens you will work it out real quick.
Oh if your are using the leash never look back to where your board is (think about this one

). And never use your arm to protect your self undless you know kung fu, etc and how to do it properly with out breaking your arm. A guy in our crew had all the gear and yep broke is arm.
The key here is get kite/water confidence then ditch the leash.
DO NOT do speed runs with a leash, your just asking for it. No protection will save you in a 30 Knot wipe out with a leash.
Me I've kited sine 1999 done all the stupid things in 10 - 50 knots and I'm a big lad. Bounced on reefs, land, into boats, rocks, beaches etc. and Killed 8 kites in surf over the years.

Only lost 1 board, but saved the kite that time.
But kite/water confidence is the key, spend time working this out before all the other fun stuff and you have more fun safer, while being able to deal with the suprises.

I'm beginning to think foot straps are a bad idea now.

Doing a bit of that no strap stuff and it's fun.