I only have 1 extra vehicle, and it's a useful truck that gets driven once a week at least. If one had more extras in the garage I can see opting for a battery tender and moving them just enough to rotate the tires and wheels to prevent flat spotting.

For me though it would be too much responsibility to have a car collection though since I tend to get attached and feel guilty when my cars get neglected.

Hi Solar,

That sounds like a good idea! Keep the battery charged - check. Burn any condensation out of the motor - check. Clean the rust off the rotors - check. Keep the tires from getting flat spots - check.

Great advice and makes all the sense in the world, but I'm guilty of letting cars sit for a long time. And not all are projects!

"...sinking on blocks (or jack stands)..." stops tyre flat spots.

Shock and strut pistons will show rust after a few months.

Oh, I forgot! I spent several weeks building a shop cart that will hold my 1200 pound JetSki. It has adjustable height and tilt, adjustable width, and it folds flat for storage.

Steve, You and I need to sit down and have a beer or two. Don't ask about my "projects" - yes, I'll get to them someday!

I have to confess my addiction before trying to answer the question.
The addiction? Norton Motorcycles, to quote "She Who Must Be Obeyed", I have a "menagerie" of them.
Some that I have I ride when I can - which isn't often enough - but alas my profession means I spend a great deal of time overseas...where I seem to accidentally find more. "She Who Must Be Obeyed" DOES NOT believe my accidental line...silly woman.
I have long ago learnt the basics of preservation storage. A lot is simple stuff, like removing the battery, draining all fluids and flush, prop up using an insulator pad between the stand and the steel of the frame, and so on...onwards to the trickier stuff. Always, keep in mind my end goal.

Is this a restoration or conservation?

How deep is my restoration going to be?

Does it need to be able to be registered (road tax) i.e. ride legally?

And the list goes on. I have 1955 Norton Manx as the factory delivered it - zero road miles or racing...try insuring that...would love to ride it but...
I have a Norton Dominator SS 1960 and a Commando Interstate that I found in Malaysia (accidentally - it leapt out from behind a tree and attacked me - my story and I'm sticking to it) that I do ride and so on.

So in answer to "What's the longest you would let a vehicle sit?" Indefinitely - depending on the effort that you put in at the beginning. Then it becomes a simple case of $$$$$$$

That's a loaded question. It depends on the following:

1. Is it a restoration project?

2. Is it only waiting for repairs?

3. Is it an "extra" car that doesn't get used much?

4. Is a specific use vehicle?

5. Is it in a safe place where it won't get beat up by the elements?

6. Is it worth the time and effort to fix?

For #1, I believe a car can sit for many years, as long as it's not getting beat up.

For #2, I think it should be fixed within a couple months or get rid of the car. Your neighbors will thank you.

For #3, If you like the car a lot, but it's an extra car that doesn't get driven much, I believe it's okay to let it sit for a few months, but it shouldn't sit for more than 6 months without being driven or at least started. If it's not that important for you to keep the car, then get rid of it.

For #4, Keep the specific use vehicle, as long as you need it and it works. For instance, some people keep a pick up truck around, even though they don't use it more than 5-6 times a year. It's okay to keep it as long as you have room to store it and it's not getting beat up by the elements.

For #5, see the first four answers above. Most times, it's okay to keep.

For #6, If it's not worth fixing, then get rid of it. It's not only a visual problem, but it's also adding stress to your life. Every time you see it, you'll hear that little guy sitting on your shoulder telling you that you need to do something about the car.

Now that I've opened my big mouth, I'll confess to some car storage sins.

I have a car that hasn't been moved in a year and a half. Nothing is wrong with the car and I should drive her more - it's a nice car.

I have a car that needs a small repair, but I haven't made the time to take care of it. I just decided to fix it and sell the car. I told my friend and he wants to buy it.

I have a very nice car that sits and sits. Why? Because every time something breaks on it, I'm out $1,000 to $2,000. I should sell it, but I really like driving the car.

I have a good little car that's a blast to drive (supercharged 4 cyl with a 6 speed manual). I should drive it, but I don't. And I don't want to sell the car. As soon as I sell the other car, I'll bring it home and drive it more.

I have a few little sporty roadsters that are either in process of being fixed or in a full restoration. I'm planning to sell two of them and keep the others. Gotta get to work on the two I'll be selling.

I have a few cars at my mechanic's shop. He's had them for too long and I need to push him to finish the repairs. Four in total - ugh!! Gotta light a fire under him!

I have a special edition car "R" that is at my other house. It has an ABS light on and I don't drive it. I know, I should fix it, so I can enjoy the car. Low on the priority list!

All the other cars are driven at least once a month. I like jumping in a car and driving it. Then I park it for a while and jump in another car. The only car that gets miles piled on it is my better half's car. All the other cars get about 5K miles at the most per year. Much better than 30K+ on one car.

This weekend, I did a nice long hike and got to thinking about my car situation. Do I need all these car? NO! If I got rid of all but a commuter car for me, my better half's car, one roadster and a vehicle for the rentals. Keep four and sell the rest. Use the money to pay off a couple mortgages. I should do this. Still trying to talk myself into doing it.

I left one sit long enough to lose interest....