The depth of your workbench should ideally be no longer than your arm can reach across it.
Woodworking workbench length. 38 39 97cm 99cm makes a practical tall workbench height. My current workbench is a stoutly built 3ftx8ft 2 4 frame with a 3 4in plywood top and big carriage bolts to hold it together. Many hand tool woodworkers though prefer a bench 1 or 2 inches lower allowing more leverage for hand plane and chisel use. A tall workbench is good for detailed work cutting joinery and for power tool use.
In most cases that number falls around 24. The small tenons are 1 1 4 thick and 2 1 2 long. About 50 of it is taken up by my metal vice drill press and scroll saw. Made precision cuts for joints with backsaws.
The standard height of 34 matches most tablesaw heights allowing the workbench to double as an outfeed support. The larger tenons are 2 1 2 thick and 2 long. Ripped and crosscut short lengths of stock to size with smaller sized panel saws or bow saws. Think big when cutting the joints for your workbench.
This is where the artisan planed surfaces and trued edges. If you happen to be the type of woodworker that works with unusually large or wide pieces then you may want to add a few inches. No bounce and no rocking for any of the work i ve done so far. But for most projects and pieces two feet should be sufficient.
Average 34 36 86cm 91cm tend to be the most common workbench height for woodworking.