Your sump has a meaningful number of gallons it moves when it cycles. Let's say a 55 gallon sump pump has its start and stop switches set pretty well. Every cycle it pumps out 30 gallons of water. You can measure that.
Pop the covers off and watch your sump pump in action.
First, check the check valve
Obviously, out the top of the sump pump, there is a "riser pipe" that takes the water up and away. Most people make the riser pipe pretty big (doesn't hurt, slightly helps) which means the riser pipe contains a fairly significant quantity of water.
If your sump pump's check valve has failed, all the water in the riser pipe will leak back down into the sump, wasting some of its capacity. It may whoosh right back in, or may trickle back over a couple of minutes.
Check valves fail from the crud in the sump contaminating their valve seals. It may take nothing more than a cleaning.
The ideal way of measuring this is turn the pump off, allow the normal amount of time between cycles, and measure how fast (e.g. in inches per minute) the water normally rises in the sump. Then, turn the pump on, let it pump a cycle, and starting the instant it turns off, measure the inches per minute in the next few minutes. If that rate is higher than the normal rate, that indicates back-leakage.
If the check valve is not easily fixed, another strategy is to reduce the amount of water inventory in the pipe, by reducing pipe size. A little pipe reduction means a lot, due to the square-cube law. If someone gratuitously used 2" and 1" would do, that reduces the water inventory in the pipe by 75%!
The filter can also matter; there should be a coarse-matter filter at the bottom of the sump intake to keep the worst crud from coming up the pipe.
A cleanout might also help; let the sump pump run it down, then use a shop-vac in "wet mode" to go after any remaining crud.
Gallons pumped is also a factor
That is where your "high/low" setting comes into play. Typically there is a float rod with two clamps on it: as the rod rises, the clamp pushes the "on" switch. As the road falls, it pushes the "off" switch. Those are adjustable.
You need to watch the action and see that the sump has a respectable working range: that it pumps down to near empty and doesn't come on until near full. But don't let it suck air!
If you want know cubic feet per pass, or gallons per pass, go online to any web calculator that'll let you compute the volume of a cylinder. For the cylinder height, use the difference in water level (high to low). For cylinder diameter, use the width of your sump. Pick one unit and stick with it, e.g. feet for everything. The calculator will give you cubic feet (or whichever unit you used). Then you can use another calc to convert cubic feet to gallons if you want.
If you want to ease the sump pump's task
And you live on property with elevation differences... then you use a French drain or Buckeye drain to lower the water table around your house. If a septic system is involved in any way, this should be given careful engineering review, otherwise you'll accidentally break the septic field and send poorly treated sewage down your French drain!