I have a mountain bike that's now about 18 months old. At the 12 month mark I took it for its first annual service. Since then there's been a problem with the front wheel coming out of alignment.
I've had the wheel re-trued a couple of times since the service now, it seems to need doing about once every 2 months. Obviously this regular attention is not a normal requirement for a wheel.
What is the normal period of time that you'd expect to pass between wheel alignment/spoke adjustment work? I'm riding the bike probably 20 miles a week on average on the road, with occasional weekend trips off-road. The wheel's gone out of true at least once without an off-road trip since the previous truing.