Normally it will last the life of the engine and is changed when the engine is overhauled.
Replace it at 60,000 miles. This is an interference engine. Serious engine damage will occur if the belt breaks. Do not neglect replacing the belt at the proper interval or you will pay big time.
That would be a judgment call on what the old belt looked like.
It should last the life of the engine and not need changed.It should last the life of the engine and not need changed.
The outfit where you are getting your engine should know if the transmission housing will bolt up to the engine.
The engine oil should be changed every 3000-5000 miles
The Ford recommended mileage for replacing the timing belt is 120,000 miles, for the 2000 Focus. I doubt that the engine changed much, if any, between 2000 and 2001.
If it is a V6 at 110,000 miles the cam belt and water pump should have been changed. This is an interference engine. If the belt breaks serious engine damage will occur. If you have not had the belt replaced STOP driving the car until you can get this done. The belt can break at any moment. On a V6 & 4 cylinder, you also need to have the transmission fluid, brake fluid, and power steering fluid changed. The coolant needs replacing and thermostat needs replacing. Spark plugs and plug wires need replacing. Air & cabin filter need replacing every 30,000 miles. All suspension and steering parts need inspected and replaced as necessary. More than likely the struts need replacing. The exhaust system should be inspected. Of course the brake system should be inspected and repaired if necessary.
Gear oil should be changed every 4,000 to 5,000 miles. Motor oil should be changed every 3,000 miles to keep the engine running clean.
every 2 to 7 years
It should last the life of the engine and is normally replaced when the engine is overhauled.
If they are bad, then yes. If not, then don't bother replacing them.