I too have excellent credit. And a pile of credit cards.
ISTM all those credit advice apps are designed to give decent answers to folks with middling credit, middling debt, and middling income. Likewise the actual bureaus and scores themselves. OTOH, if you’re an outlier in any or all of those three aspects, their advice is comically obviously the result of a one-size-fits-all app being applied to a corner case.
Here’s a funny story:
Last year I moved into a new residence and bought all new furniture and housewares end to end. Spent quite a chunk of money in just a few days. Each of the TV/electronics store, the furniture store, the mattress store, and a glitzy housewares store all offered come-on deals where I could open their store credit card, charge my purchases, and pay only the minimum each month with zero interest. As long as I made the balloon payment after 1, 2, or 3 years depending on which card it was. If so, I’ll have gotten a 1-, 2-, or 3-year interest free loan of all that money.
BUT … [cue ominous music] If I failed to make the balloon payment timely, then 20% or 30% interest would be retroactively tacked onto the balance from the purchase date forward. And then I’d owe my soul to the company store. Nice trap they set for the unwary and the unlucky. Not one I’m going to fall into.
Anyhow, I open 4 cards in the space of about 3 weeks. And charge the furniture card up to the hilt because they would not approve a card for the total size purchase I was making. So I put as much as I could on their “zero interest for two years” card and the rest on one of my existing I-pay-in-full-every-month cards.
Now comes the kicker, and why this story is sorta-applicable to your situation …
Opening & using these 4 cards cratered my credit rating. 820 turned into 720 overnight. Why? The app said it was because of 4 hard credit report pulls in 3 weeks. Plus now I had a single card with a high balance to credit limit ratio AKA credit utilization rate. Unlike all my other cards with zero ongoing balance. Idjits!1!.
Fast forward a year to now, and my credit score has fully recovered even though I’ve paid but a pittance on any of those 4 cards. Next month I’ll need to pay the balloon on the one card with the 1-year-same-as-cash deal; the others will mature next year or the year after.
But the credit score reporting app still sees those 4 hard credit pulls within the last 2 years (WTF?) as a negative. But they can’t be adding much negativity to my score when it’s 820. And now they’re not worried about the high utilization on the furniture card. Which is still at ~95% of the limit; even with no interest expense, the minimum payment is eating that elephant with a teaspoon. WTF2
Go figure? Like I said, one-size-fits-all doesn’t.
My bottom line on this story for you:
If you do decide to open a card for some reason, don’t do more than one, and don’t put a big balance on it. Use it and pay it off for a couple months and see what that does to your score, and if the results are positive enough to matter to you, do another one WAG 6 months later. I actually expect you’ll see a short term dip in your rating but it may recover after a few months to higher than it was.
Separate to all the above …
“Room to grow” what? A better score? A greater total amount of potential credit? For why?
I do know that when I bought a car a few months ago being 800+ saved 1/4% APR over being 799-. It was a bit of squeaker versus my recovery after the 720 flail, but it had broken above 800 by then. Though strictly by luck, not skill or effort on my part. I suspect the car loan also had other, even higher, interest rate tiers for people significantly below 799, but I never got those details.
Beyond that, I’m not sure what utility a higher score has. We’ve just seen that high scores are short-term brittle, but can recover if you stay on top of it.
As to how many cards, I’ll start by backing the conventional wisdom upthread of one and a spare bare minimum.
I go beyond that and have one from a gasoline company that gets me ~5% off on their gas. And which I use only at the gas station so if it gets skimmed all the rest of my autopay and stored cards at bunches of websites don’t need to be updated; the only damage will be waiting a week to get a new gas company card.
I also have a couple of store credit cards for places I shop regularly where the card carries a ~5% discount.
But really two+gasoline is what I’d call both the minimum for safety and a reasonable maximum unless you’ve got particular reasons to have more.