Here is a good blog on whether or not you should renew your warranties on firewalls, servers, routers, software, etc. It is written by a friend of mine, Ken Zimmerman, at Trivalent Group out of Grand Rapids, Michigan. He provides some points you should ponder that are well thought out.
Here are a couple of his paragraphs that really got my attention:
Truth be told, in IT, nearly everything you purchase has some sort of maintenance agreement that goes along with it, from your antivirus to your backup hardware/software to your firewalls, routers, switches, etc. In some instances, looking out for the best interests of our clients means giving the best information possible and having them let you know what risk they are willing to take. I hate to say it, but some maintenance renewals are a lot like insurance. It all comes down to the risk versus cost multiplied by probability.
My honest opinion is that, first and foremost, you need to make sure that you are covered regarding things that protect you on the security side of things. A firewall ultimately is the lock on your door. If you don’t keep the lock on your door updated, how useful is it? This goes for antivirus and malware products as well. They are only as good as their last update, and you want to make sure you are able to get the newest updates and releases. With viruses and ransomware flying around on a daily basis with so many different variations, I look at it as a very short-sighted thought not to renew this type of maintenance renewal.
Here is a direct link to his column, What is the Value of Maintenance Agreements?

You want to enter in a fully burdened labor rate for this field. What that means is that you want to take the base hourly rate, plus 25-30% for employer payroll taxes, benefits, vacation/holiday time, etc.
Smoke testing is a type of software testing performed by Alvaka after a software patching sequence to ensure that the system is working correctly and to identify any misconfigurations or conflicts within the patched system.
This is a basic cost calculator for you to compute your typical monthly cost for patching your servers, PCs, laptops, tablets and associated application software. It also forms the basis for you to begin calculating your Return on Investment for software patching, or for comparison with alternatives to the manual process of patching operating systems and application software—such as Patch Management as a Service, also known as Vulnerability Management as a Service.
Smoke testing is a term used to describe the testing process for servers after patches are applied.