Regression in Predicting Tenancy Lengths
You may have done this already, but if your target values are positive integers, it could be worth transforming your output layer in such a way that constrains it to take an appropriate range of values.

Tenancy length values presumably have some recognisable distribution that might fruitfully be modelled by a known statistical process (Poisson process, survival analysis, etc.), and so instead of using your NN to predict the tenancy length directly, you could use the NN to parametrise a relevant probability distribution, and make a point estimate of that distribution in your output layer.