2001 Ford Focus has rust?

My friend has this car and I noticed some rust spots below the driver and passenger doors. I'm not sure how bad the rust is but I was wondering how long would a car last with rust? It had like 150 thousand miles but runs great. To factor in we live in Ohio so it gets pretty snowy in winter.

Really depends on how bad the rust is, and if the underbody is rusted. Rust on the rocker panels don't mean much. Just cause a car is rusty doesn't mean it's not gonna last. The body panels can be replaced, so rust on those doesn't matter as much. But if the frame is rusted, then the car is shot. Things like brake lines are in a gray area because while they CAN be replaced, they are costly so it really depends on if your sick of the car or not.

Wire-brush cup in an electric drill will remove surface-rust, if it goes deeper, then have a garage cut it out and do patch-repair on the 'rocker-panels' (we call them 'sills' in the UK) and in the worst case, you may need the whole sill panel removed and a new one welded-on. When you have the repair done, get them 'stone-chip' painted, which is a thick, rubberised paint like smooth peanut-butter, that stops gravel flicking up and chipping the paint, causing rust. Also, consider a pair of 'side-skirts', which look sporty and protect the panel.
http://www.ebay.com/...t&_sacat=0

Hi so here we have a 13year old ford and you leave in a state where salt is used on roads when the snow and ice are on the roads. Well here in the united kingdom same car same type and model. A 13 year old car is likely to fail the old MOT test here which would mean it then goes to the scrap yard as un roadworthy.

Water is getting in the door at the window seal at the bottom, fords are bad about this, there's a rubber plug at the bottom of the door, remove it, and take it to a body shop and have it repaired

Have body shop repair the rust spots before it gets worse

Good

Body rust will have no impact on how long the car will run or will be legal to drive in a state like Ohio, which has no yearly vehicle inspections to worry about passing etc.,

Worry about the condition of the underbody, as others have already said. If you're concerned but not sure how to identify structural rust problems on the underbody of a car, have a competent shop inspect it for you. Surface rust on the underbody should be expected, especially since you drive in a salty winter environment, but if the rust gets severe it can start to weaken important parts (the lower A-arms, the front subframe etc.,). The car is fairly old now, but probably not quite old enough yet to have severe structural problems from rust. Still, if you're concerned then by all means have it checked out by a shop you trust. Better to find out that way than while driving, by total surprise.