After trying a technology, which of the following is most important to experience prior to making a decision to buy?

One of the challenges many organizations face is the deployment, maintenance and operational costs are never estimated or understood outside of the initial licensing costs.

For us it was always TCO - total cost of ownership. And that includes everything possible. And one cost few consider - Exit cost. If you adopt the new X technology, how difficult and expensive is exit or switching in a few years? Always consider having an exit strategy