Depends on what your plans are. Plan on buying RE? If so, 30 is too many. I had 29 cards in 1998 when I bought my house. Broker told me to close some cards - I wound up having 8 cards. And 8 is how many I have today.
Have no plans to buy a house? 30 is fine. I managed well with 29.
Banks son't like to see you with too many cards - they get jumpy if you have access to too much credit..
New York Yankees - 2009 World Series Champions. 27... and counting.....
The more cards you have, the better it is for your FICO score...up to a point, anyway. That "curve" is pretty healthy on up to 5 or 6 cards, then begins to flatten, and by the time you pass 10 or so there's really no significant benefit to having more.
So I would triage the cards. The older they are, and the higher the CL is, the more valuable they are. The newer they are, and the lower the CL, the less valuable they are. If a card is your oldest reported account, don't close it.
- - - - in a credit-scoring postnuclear Stone Age...