ITM is a good goal for every tournament you play. But it isn't a great metric to measure. We obviously want high finishes in tournaments, like the top 3% or so. The thing about getting to the final table and then getting to the top 3% is that you still have to cash first. So for me it is a good thing to watch for. But as was mentioned, you can't tell if you are winning or not by measuring this by itself.
ROI is the right metric for this. " ( Winnings / cost ) - 1 " is the percent ROI formula. If you have a negative ROI but are cashing 13% of the time, then you know enough to be competitive, but you need to develop your game further. You could have a 30% ITM and still not have a +ROI. Same story with this - it means you are competitive and may only need some tweeks to improve to be +ROI.
+ROI is very difficult. Making the most of every ITM opportunity is necessary to increase your ROI. ITM is +ROI. Busting before the bubble is -ROI. You will see a lot of discussion that we need to go for the win because that is where the money is. This is true. But you cannot win without first cashing, then getting to the final table then winning the thing. Take it in steps or mini goals.
Good luck and God bless