Buy a car camping tent made by a backpacking tent company.
Think heavier poles, heavier zipper and a footprint. Not just cubic footage.
Big Agnes is a great choice.
Wind causes many early on tent zipper failures.
Blowing sand and dirt.
Clean your zipper with a damp sponge and when it starts sticking go with silicone. At home use the silicone spray that you use to lube your garage door or regular door hinges.
Or buy this product to be a pro and pack it in that never ending repair kit:
Cabela's: Gear Aidô Zip Care Cleaner and Lubricant
Gear Aidô Zip Care Cleaner and Lubricant Regular Price: $4.99
Look for a door design that makes it easy to open and close one handed without putting stress on the zipper. If the door is hanging down at an angle away from the closed door as you're moving the slider that is not good.
A fairly straight run down from the top then across the bottom is best. The more curves in your zipper to more you get to know the zipper repair department.
Buy a tent with two doors.
That's great for you and your partner for convenience.
But if one zipper breaks bad then you have options if you have to sew the offender shut in lockdown.
Needle and thread can be used to shorten a zipper.
Say a bad spot is starting to go on your zipper. Just sew that area together so that you can keep using that zipper for the trip. Hopefully you'll not have too short a run.
If you have to pay for a zipper replacement don't relive history. Go with a heavier zipper.