For Room Correction DSP/Software- How often do you use it?

I’ve noticed more frequent questions regarding room correction/analysis tools lately- what to buy, what’s best and so on. I don’t own these tools as I hired out the service when setting up my room/equipment and have not felt the need to do so again.

For those that own such devices how frequently do you actually use it and what drives the need for its use? 
What is achieved from its use that is outside of more traditional approaches such as speaker placement, room treatment and/or component matching?
In the end did you find the purchase of the equipment a good investment? (whether low budget or expensive)