This year I am reviewing a sport-related product which is very seasonal. It is a tangible product and not many reviews exist in the market.
I’d like to build something that becomes a great resource, but I’m torn between making this a yearly review or creating a definitive guide that I just update each and every year. In terms of creating linkable content what is the best approach?
I’d go for the updated definitive guide, myself. The advantage is that the page builds up SEO reputation over time. Just make sure it stays up to date, and that this is obvious to visitors. For example, either avoid including a post date, or also include “last updated on” info as well. And perhaps have a “what’s new” feature at the top of the page that explicitly signals that the page is being kept up to date. That’s my suggestion, anyhow. 
Hey pinch,
I would certainly go for a definitive guide over yearly reviews. It gives better SEO ranking (as mentioned by Ralph). The most shared articles online are usually created and maintained over a period of time, simply because they contain useful information that are accumulated over time! It would be better for visitors to know that they are reading the latest and most comprehensive guide, rather than trying to figure out which is the latest review (if you were to go for yearly reviews). It would be a good idea to list down the updates you made each year on the top of the article, which signals to the readers what have been changed. Also, I personally would love to see what changes have been made over the years - it gives me the confidence that the latest product is the best one thus far!
I guess I would have to third the definitive guide. As for the purposes of SEO I think it would be more beneficial. It would also be less time consuming re-writing things where it might not be necessary.
On the other hand a yearly review is not the worst route to go down it could be just as shareable due to current following and readers. A yearly reviews offers you the opportunity to re-engage with everybody and even find new customers/readers of the review due to it being a “new” publication.