Avada Software's licensing metric is very good because the license fees are based on the number of connections (which have not increased for us very much over the years) rather than the CPU processing power (which increases significantly whenever our hardware is upgraded) or the number of users (which has increased for us a lot since our original purchase).

Because the licensing is at the QMGR level, you need to have at least a small cushion of licenses for occasional enterprise needs. What I find most onerous is that we also want to use the tool during our quarterly DR exercises, but in order to do so we still have to pay for these licenses (albeit at a reduced price which also reduces the maintenance costs). These QMGRs are really only needed 4 days a year barring any significant data center outage.

 I was not involved in the negotiations.

Start small, then increase licensing later as per your demand.

Our internal budget calculation model incorporates the pricing per endpoint for any new projects. However, as our footprint for distributed queue managers shrinks as part of our shared middleware hub deployment, the initial licensing and support costs have been reduced over the last five years.