I know landlords think longer leases help avoid vacancies (I'm sure that's why you're considering it).  

Vacancy is expensive for me with rent at about $1500 per month.

No bank is going to let you be a 6-unit landlord without some capital behind you to fix AC units and cut the grass and absorb a vacancy. 

I also have reserves for my rentals that can handle 1/2 vacancy for 2 months. 

I don’t want to be insensitive , but if she moves after the summer it is extremely hard to rent out the house and could have a 6 month vacancy . 

Vacancy 8%, Repairs 5%, and Capex 10%.

You will have less problems with vacancy, military families move at all times of the year, and your active duty tenants will have a consistent paycheck.

If not, selling might be a good option if you don't want to worry about vacancy or having to renovate the house at all to get a new tenant, especially since you're remote. 

Id like to add one more element regarding the office marketCompanies will realize that entire departments will be able to continue to work from home causing office vacancies across the board. 

@Bosko MijatovicWhat are your vacancy laws?