My current lease term duration states it shall start from XXX to and including XXX. 

Duration: 1 year 4 years later Tenant 2: Pays all the fees plus 150 late fees, stays a year and I have to evict in a year. 2,600 in eviction costs minus 150 for late fee from before.

Our lease says in capital bold letters that only the approved animals are allowed on the property, no other pet visiting, sitting, fostering, etc. for any duration of time, to make it 100% clear.In any case, you can demand the tenant get rid of the unpermitted animal since it's not on the lease.

The landlord on the other hand is stuck with the tenants for the duration.

Simply, the cost/benefit isn't there for them.I wouldn't address this as a concern right now because it will damage your immediate relationship with the tenant and remember that you still have to deal with them for the duration of the lease!

If the claim is proven, the Hearing Officer will determine the percentage that the usability of the rental unit was reduced and the duration of the reduction.

Here is some language from our leases:When terminating the Lease, Tenant will allow Landlord to (i) show the Premises, (ii) install a lock box on the Premises for access by real estate agents, Landlord representatives and maintenance staff and other agents and (ii) conduct at least two open houses of 4 hours maximum duration.

The time period under consideration is also a key ingredient: your above post seems to implicitly assume an annual period - this is both a common and convenient window, but other durations may also be used.If a landlord choses not increase rent on a tenant at every opportunity that presents in the short term, it does not preclude an optimized performance of the property over the longer term.We have an instance right now where we have chosen not to charge market rent.  

Are you able to estimate from the damage the duration of the leak? 

It is not about this repair it is about them walking all over you for the duration of the tenancy.