The general rule of thumb is that you’ll need leaf spring repair once the vehicle surpasses 200,000 miles. As usual with most auto repairs, suspension components can break or malfunction much, much sooner than 200,000 miles. Problems with leaf springs can occur well before 100,000 miles if you drive on bumpy roads or exceed your truck’s load tolerance.
Checking your leaf springs every 12,000 miles should suffice to catch suspension problems before they can cause further damage.
Pro Tip: to get the most out of your leaf springs: Don’t forget to clean them regularly! Over time, corrosive grit, debris, and grime will damage any suspension system. Using an ordinary degreasing spray and a wire brush will work well enough to keep leaf springs as clean as possible.