I grow blueberries here in Madison, Wisconsin. I have to test each individual bed every spring. Our native soil is alkaline, pH around 7.6, so I have to keep adding sulfur to the soil in order to get pH below 6.5. I have learned how to do my own pH testing, to keep the cost down. In your situation, I would be making compost from garden refuse and lawn clippings, and adding compost to each bed every spring. If the veggies look healthy and the produce is good, I would not do any testing. The plants will tell you when they need something added to the soil...

If you really want to test, consider cost and sample size. You probably don't need to test every bed - 50% should be decent enough.

The people at your counties office of the Rutgers University Cooperative Extension Service will tell you, correctly, that you need not have each bed tested seperately, unless you suspect a problem with one bed. They will tell you to sample each bed and mix the samples all together before submitting them. If you plant on growing things in one bed that requires a much different soil then the others you may want to consider having that bed tested seperately from the others. If the beds are very large and seperated by wide expanses of lawn, or have other conditions that might make the soil different, you might want to consider testing that seperately.
Some of my planting beds do get tested seperately from others, one is tested every year, but they are large (4 feet wide but quite long) and in different areas of the yard with some near the road and others long distances from that road but with other conditions that might influence what goes on.

Here is a link that might be useful: Rutgers CES

Thanks all. The beds are relatively small - my yard is only about 40x40 and the beds cover maybe 40% of it. I also try to rotate the veggies, at least as much as I can in such a small space.

I also have almost no grass or trees, so I'm low on compost. I do have a pile that I started two years ago, mostly veggie scraps and paper or straw for browns - but last year it wasn't even close to ready so I couldn't use it. I'm hoping this year I'll have some that's useable.