When should you consider ETM?
It is the most convenient option when your own in-house team already has developers, but there are some limitations in the in-house talent pool.
Ongoing projects that expand gradually over time and substantial manpower is required to maintain.
Long-term projects with an evolving set of requirements wherein the required technologies are not available.
Projects which have secondary projects within them, and you prefer the extended team to work on the secondary projects, so that the in-house team focuses on the main project in core business.