I did it myself about 12 years ago on my prior boat. Not terribly difficult BUT you must be meticulous in making sure that every square inch is wax free. In my case I used an Interlux cleaning
agent and lots of rags. I still see my old boat from time to time and it still looks good.
I'm wanting to re-do my decks now but I'm going to try something different. For one thing, the price
of Awlgrip is obscene. I'm going to try a product called KiwiGrip. A water
that appears to require much less extensive prep with easy cleanup. I've ordered a quart to try in an inconspicuous portion of the deck and if I like it, I'll buy a gallon and do the whole deck.
that I've read have been favorable, it's about $40/qt, and the special roller allows one to choose just how agressive the non-skid aspect is. Plus, it would duplicate the existing non-skid pattern already on my boat. It is estimated that life expectancy is around 5 years in a high traffic area and 10 years in high traffic areas. The claim is if an area becomes worn just add a quick additional coat.
There are a great many other products out there as well. Look around. While none may be difficult, they all require time and work. I'd not want to do a job and have to repeat it too soon. Also, if the job doesn't turn out right, it can be a bear trying remove the stuff to re-do.
I'm in the midst of so many other chores on the boat that it will be a while before I try the KiwiGrip. Probably a month or two. Go ahead and google
it if you want more info. If you still want to use Awlgrip, feel free to PM me and I'll provide all the tedious details of what I did. This topic has already been discussed on this board. One felllow's attempt went south. You'll find a lot of differing opinions, even on the application of Awlgrip not to mention endorsements for other products.
I don't know where you are but locally I suspect to have a pro repaint your deck would be about $5k. Most of that is prep labor cost.