HVAC work lives on the equipment, and rented software files it under the ticket
The jobs that pay best in this trade depend on knowing what is installed at each address, and most rented tools treat that as a notes field.
Think about what your office juggles in a week. Maintenance agreements with visits due by season, equipment with model and serial numbers, manufacturer warranties waiting to be registered, and failed parts waiting on a credit from the supply house.
Add replacement estimates with several options each, financing applications, permits on changeouts, and technicians who spotted a rusting coil but had no good place to say so.
A general field service app can hold some of this, usually as attachments and free text. That means nobody can ask a simple question, such as which agreement customers have a system old enough to start the replacement talk.