Learn me - shopping for used snowboards

As the topic states, I'm looking to learn about shopping for a used snowboard for myself and also my oldest son. 

The big present for the boys for Chanukah/Christmas is a season pass for the local ski area that's less than 30 minutes away. As a result I also got one, so I can keep an eye on them  (that's my story and I'm sticking to it).

I went with a seasonal rental from a local snowboard shop for the 13yo, I'm sure he's going to from more in the next several years.  But for the 18yo and my 49yo self I'm looking at buying used. 

So what I need to know is what are the things to watch out for when checking out a used board/binding/boots, and what brands I should be looking for as I shop. 

As an example of what I'm seeing is this on that I'm supposed to check out on Thursday:

Carbon credit

I wear a size 8.5 shoe and am 5'7", so it seems like it could be a good set up for me, or maybe my son (also 8.5-9 shoe and 5'4").

I plan to buy new helmets for all of us, and already bought a K2 with MIPS for the 13yo. 

Gnu / Lib Tech make very nice boards, but you will pay a premium for nee and used. IME, they tend to be on the softer / more flexible side. The Carbon Credit is a popular option. 

What kind of riding do you anticipate doing? Big carves? Technical tree lines? Jumps or park stuff? All mountain?

I'm an all mountain guy, myself, so I tend to steer towards boards that can do a bit of everything. My personal favorites

1) Arbor Coda - any condition, any terrain, this stick was ready. I leveled up my skillset tremendously on this board.

2) Ride Warpig - the steeper the better. I've borrowed one and immediately fell in love. It's on the short list, if I ever find one at a good price.

3) Gnu Riders Choice - soft, but surprisingly stable. Very tweakable, helped me pushed the boundaries when I first got serious about snowboarding. 

I've bought and sold a bunch of boards on FB and or Craigslist. The big things to watch out for are damaged edges and holes in the base. 

I have no affiliation with this site, but http://www.angrysnowboarder.com/ has been a good resource for honest, albeit a little biased, reviews on gear. 

In reply to birdmayne :

Thank you for the info. 

The local mountain is Wachusett, which is small and relies a lot on man made snow. The typical conditions are a mix of groomed trail with an ice base that gets exposed over the course of the day. 

My goal for the season is to improve skills and confidence on a variety of terrain and conditions. As a result I figure I'll be exploring different trails and terrain for carving, tight technical turns, small jumps, and rougher sections. I'll probably explore the terrain park as well. 

Since the boys and I will probably overlap on board sizes we can also try different boards during the season. I figure after this season I can look to upgrade or get a different board to try based on this season. 

I ended up buying the one I had linked it above. 

I met up with the guy tonight and tried on the boots and they fit really well, actually they fit better than any I've had when renting. The board was in good shape, some minor marks from use, but no big dings and the edges had no gouges. 

Now to find another board and boots for my oldest son.