What you add to your life should justify what it displaces.

Nothing enters a full life without pushing something else out, so the real question about any addition is not whether it is good but whether it is better than what it will displace. Comparing against nothing makes everything look worthwhile. Comparing against what leaves is the honest test.

When considering something new, name what will get less of you because of it. Then decide whether that trade is one you would make deliberately. Often the answer changes the decision.