What's the cost?
And did you receive any offers for this domain yet?
About the renewal factor, it's an important one to consider but relative to other factors like how many offers did you get for that domain? What about the traffic it gets? etc.
It takes time for the right buyer to show up for this kind of domains especially for .guru names as far as I can see.
Auction is good way to gain exposure and attention if you set the reserve price to your desired and fair value, and your domain can get that attention easily IMO.
Wish you the best!