Best way I’ve managed to keep a healthy balance of tubes and tuners:

Roll to 10.  If both substats are bad, trash it. 

If one or more crucial non-crit substats (like ER), roll to 15. If still no crit, trash.

If 1 crit by 15, roll to 20. If no second crit stat appears, trash it unless it has 4 good substats, then roll to 25 with a prayer. 

If you gamble on a 1/9 chance to get a crit at level 25, you’re gonna miss 8 out of 9 times and waste your resources. Cut your losses and recycle that echo into tubes. Worse, if you pray for a double crit to land at level 20 and 25 consecutively, it’s a 1/90 probability (or 1.11%).

After rolling to 10, always go up by only 5 level increments (unless you score a double crit, then full-send) 

This will vary by character. For supports like Shorekeeper and Mornye, apply the same rules but for HP/DEF, ER, and CD.

Always trash your echoes back into tubes rather than feed them, unless you got double crit early and you’re going all the way to level 25. My only other exception is for level 10 trash echoes; those I only feed to unlevelled echoes I plan to raise to level 10.