This reminds me of something I read once on the $700 billion stimulus package.

I texted the tenant to remind him to change the AC filter in accordance with the lease.

I think its a good idea to contact your tenants and remind them of items that require their atention this time of the year.  

I would like to find a software which sends tenants an email when a friendly reminder that rent is due and if late the new total everyday until paid.

Turnover Cost - #1 Vacancy We do our best to closely monitor the renewal dates (auto reminders weekly) to minimize the loss of income from vacancy during a turnover.

-is it illegal or immoral for a lien holder to send a friendly, reminder letter to pay their taxes?

Glad i could help you last week,  I want to remind you there is a $50 lockout fee in your lease.

On the 3rd or 4th, if I have not received rent from someone, I send them a text (my tenants all agree to be contacted this way) that says " Hi tenant, this is a friendly reminder that I have not yet received your rent.  

By "involved owner" meaning I have to ask / remind them every silly thing ?  

Account Closed thanks for that I really appreciate the boost in confidence being reminded of all the resources that are out there.