When there is a big snow, does it make sense to shovel sporadically or wait til it's over?

It depends. Often the snow falling is light, but waiting x hours until the snow stops may result in either a drop or increase in temperature (or both). If it gets warmer and the snow gets heavier, you may wish you had gone out earlier. If it gets warm and then cold again, you’ll deal with the additional challenge of an icy layer.

But there is the issue of the street plows. The piles at the end of your driveway will be significantly-heavier and more difficult to manage than anything else. I find that periodically taking care of at least this part throughout a snow storm really makes things easier. If we are getting 18 inches of snow over a 12-hour period, I don’t want to wait until it’s over to deal with the 3 feet heavy ice-filled wall the snow plows have created for me. I’d rather go out multiple times.

If you live in an open area or out in the country you wait until the wind stops blowing, otherwise all the work that you accomplish will quickly be covered by drifting snow. I learned the hard way when we first moved out here. I was such a city girl.~

If the Strong Young Teenage Boys are more likely to be out hawking their brawn after it stops, I wait and hire them.
If it looks to go on a long time, I go out from time to time so I’m not stuck if those selfsame Strong Young Teenage Boys don’t appear.

And my house is cold, so it helps me to warm up. And it justifies the consumption of cookies.

I have a snow blower. I wait until the snow stops blowing and the depth is at least 3 inches. Below that I don’t bother. Ideally I will wait until there are drifts just the depth of the intake, 21 inches deep. The blower loves it!
If I were hand shoveling I would do it periodically. I think it is better for you physically and psychologically. The task does not seem quite so daunting when you can clear it out quickly even if you need to do it more often.

Wait until it’s over.

If it’s a light, dry snow you run the risk of drifting snow obliterating your earlier efforts, as @jonsblond describes.

If it’s a heavy, wet snow, you run the risk of baring the hard-surface, traveled areas, enough for melt to start. If the temperature drops, you’ve created a sheet of ice under the fresh snow.

Seems like every time I’ve thought I would get ‘an early start’ on removing the snow, I regretted it.

Of course, you live in an area with a lot more snow than I get. 8+ inches in the Midwest and life comes to a halt.

What’s snow?

If it’s going to snow for over 6 hours, usually I’ll go out and shovel while it’s snowing. The snow here is usually thick and heavy, and my shovelling task is a winding staircase. There’s a point where it becomes dangerous if you don’t stay on top of it. And, of course, neighbours who don’t shovel will go up and down the stairs, packing it down under their footprints. That snow becomes very hard to remove – and if you don’t get it off by the next day, it becomes ice.

It is all a matter of timing. I estimate how long it will take to shovel and how many remaining hours of daylight there are. I wait until the two about coincide.

I have never shoveled snow in my life.

@Dutchess_III Well, I’ve been getting a crash course in it this year.

@Dutchess_III I offer training classes for free.

Never needed to shovel.

If it’s going to be very deep I shovel while it’s snowing a couple of times. Unless it’s windy, then I would more likely wait until it stops.

Even if you wait until the snow stops remember that you shouldn’t shovel snow for a very long time. Snow shoveling related cardiac arrest is a real thing. It’s easy to overdo it and not realize it until later. Some advise that people over 60 simply shouldn’t do it. The snow shoveling related heart attacks happen to people much younger than that though. They happen every year. It’s more strenuous than most work outs, plus the cold can cause a rise in blood pressure and narrowing of arteries. Not a good combination.

I would personally say if it allows you to shovel sporadically that might be best, in the end you will have less to clear away than waiting and having quite a bit to clear. But if it’s coming down strong the whole time it would be best to wait.