Switching from Month-to-Month to 1 yr Lease

[Robert P.]

My tenants are on a month to month "at-will" agreement, and have been for a year. I like month to month as it leaves flexibility for both parties. I have now been reading a lot on here and everyone is under the some consensus that Spring/Summer is the best time for renting out your apartment. 

My question: Should I continue to let them stay on a month to month lease and hope they don't end up leaving on an off month eventually (Jan/Feb/etc.) 

OR

Do I have them sign a year lease now and continue renewing in yearly increments in order to maintain the correct cycle of tenants moving out/in during the spring/summer months?

My concern is how the tenants will take this. Good thing? Bad thing? I just don't know!! They tell me they want to stay for a minimum of another couple years, but that could change in a heartbeat. I take it with a grain of salt. A year lease is something in writing. Thoughts?