A gravel driveway is a small road, and it should be built like one. Most failing gravel driveways in this region come down to one of three problems: no proper base, no crown, or no drainage.
The base is coarse crushed stone, laid 6–8 inches deep and packed down in layers. This is the layer that carries the weight. Skip it and no amount of surface gravel will save you.
The finished surface is a finer packing gravel that tightens up and sheds water. Two to three inches over a proper base, shaped to a slight peak down the middle so water runs off to the sides.
That peak down the centre is what separates a driveway from a mud pit. A gentle slope of about 3–4% from centre to edge is enough to move water off without the gravel sliding into the ditches.
Drainage is the third leg. Ditches on both sides where possible, properly sized culverts wherever water collects and crosses, and shallow channels cut to steer runoff away from the driveway.
Built this way, a rural driveway in our climate needs only a light levelling every 2–4 years to stay in good shape.