Mileage question is spot on-those 3rd-gen Foresters start chewing bearings around 120k-150k pretty reliably, especially if you’ve got road salt history up north. But let’s not lock in on that yet; I’ve been burned calling “bearings!” too early on similar hums that turned out to be tire cupping from bad alignment (Subaru’s AWD loves to toast fronts unevenly).
Quick road test to narrow it: At 55-60mph on a straight empty road, swerve gently left then right a few times. If the hum gets louder turning one way (say left), it’s likely the opposite-side (right) bearing under more load. No change? Lean tires or even a worn CV (check for that play we mentioned). Evidence from my ’07 Outback with 140k: exact same symptom, swerve test pointed right front, and yep, bad bearing confirmed by the spin/grind.
Pro tip before jacking: Rotate tires front-to-back if you haven’t in 5k miles-free test if noise moves to rear. Seen that fool a few shops. What’s your tread look like, cupped or feathered? Pics help spark the diagnosis debate here. Drive safe till you check!