Dave from MN,
5-7 years is really long term. We do 2 year contracts.
The end-time of the contract is what we question... though our renter is really great (I think we are going into years 6 & 7), what if he opted out at the last moment and left us holding the proverbial bag? Then one could have a difficult time finding a renter that year.
I think the renters just want a spring end-date just in case they did not get their crop off the land. But that virtually never seems to happen now days. I kind of like your December end-date. It seems safer from a landlord's perspective.