Mechanic says adding oil is normal...every 2 to 3 weeks?

What is your question?

I have a 2002 525 wagon. It has 95K miles. the check engine oil light comes on every 2 to 3 weeks, at which time I have to add a quart of oil. Is this normal or am I heading toward a small fortune fix? I am just about at wits end with all this spending and want out if this is the case. Please help. mechanic says this is normal for high milage beamers. Thoughts???