These work great. Having two people to do it one moving the vehicle and the other moving the blocks saves a lot of time. But one person can do it; you just have to keep getting out of the vehicle. We cover and store our trailer in winter, and they will be perfect for keeping it elevated off the ground when the snow flies. We will really give them a test up in the mountains this summer, but for now, in the driveway on gravel, they are perfect also for keeping the tires off the gravel. We had been using carpet to keep sharp gravel edges from piercing the tires constantly. They are easily stowed in the large cargo box on the back of our 16 foot single axle trailer. Also, you cannot just drive away and leave them; you have to work to remove them, so you will be attentive about getting them back into their storage container for traveling. Unlike wood and rocks, these are much easier to use.