Northwest and Budget are my co's preferred carriers. Some say put all the miles in my Northwest account, and some say keep them separate.
What would you do?

Thanks from a newbie!

Well, here's my advice. I say keep them seperate and here's why. As a partner of the WorldPerks program, you'll earn 50 miles per rental day. Given that your average rental may be let's say $45. And of course as a partner you only have one way to use these miles - as Northwest miles. If you were to stay with the Budget Perfect Drive program to collect points, you're basically in at a point per dollar spent and can transfer to WorldPerks later on....or to American, Delta, Southwest or United. And if you are really vlever, you can port the miles from Perfect Drive to Delta and then to the Hilton HHonors program for some free hotel noghts - all choices you don't have with earning miles direct from WorldPerks with Budget as a partner. Good so far. But it really is only good if the value proposition works. OK, let's say you rent 20 times averaging 2 days a piece and paying $45 average. Total WorldPerk miles earned as a partner would be 2,000 miles. total earned with Perfect Drive converted back to WorldPerks is 1,800 miles. You might look at that and say, looks like partner with Northwest wins. I disagree. Because as long as you control your car rental booking, you can earn double points from Perfect Drive by booking online with them, meaning that instead of 1,800 miles with northwest, you'll earn 3,600 miles of several different kinds (other airline partners and of cource chance to convert to Hilton HHonors from Delta, etc.

Because the number of miles here is pretty inconsequential to the bigger picture (meaning that they are unlikely to make or break you miles portfolio) I'd take the advantage of Perfect Drive and enjoy the many more choices you have.

There is one caveat - you can only convert into airline miles in increments of 500 airline miles (600 points) which means the conversion is not as liquid. But since you can't double dip, I say know when to hold them and stay with Perfect Drive.

Hope this helps as another perspective.

Yesterday's Wall Street Journal indicated that Cendant (who owns Avis) is looking to buy Budget, if Budget will declare bankruptcy first. This certantly has me thinking about my PerfectDrive points.