Which card to use??
 

I currently have the Ritz Carlton Rewards card, the Bonvoy Boundless and the AMEX Bonvoy Business card. I have the RC card attached to my account as my primary card but is there any reason to use one of the other cards for any stays? Also I believe the Bonvoy Brilliant is not available to me since I hold the RC card or has that changed? I have already qualified for Platinum for next year and expect to reach Titanium by late summer.

Perhaps just to keep the cards active, if you are not otherwise using them, so they are not cancelled by the bank for inactivity?

That is more common for cards with no annual fee.

Or for record-keeping purposes, to segregate business stays.

I had a JPM Ritz-Carlton Visa for a couple of years, and they gave status at $75K spend, but you do not seem to need that this year.

If one gives more points for Marriott Bonv°y stays than the others, that simplifies the decision.

I have both the Ritz and Boundless cards also. They both give you 6x @ Marriott. I started using the Boundless as my default because you now get an elite night credit for every $5000 in spend. I use the Ritz card when I am staying at a Ritz and using one of the Club upgrade certificates.

I have been using the business card recently for some of my gas and diesel fuel purchases due to the 4 points per dollar category. I have the AMEX Blue business that pays 2 points on all spend up to $50,000 but I am likely to meet that limit so I want to try and use that for other spend that is not eligible fo any points bonuses. I have not been using the Boundless card very much and based on bigdaves suggestion maybe I should.

That is an excellent point. I believe I knew that but had simply forgotten about it.