For this question, I think the discussion needs to be about the specifics, meaning what kinds of weapons need to be installed and what level of protection they give. The third important thing is the readiness for maintenance and the spare parts of the armoured vehicles, whether they're new ones or the decommissioned ones.
As you can imagine, their usage in the battlefield is much greater, many times heavier than on the training bases, so for each specific type of vehicle, all things together, including the sustainability of their usage, are of crucial importance.