Does the car run unevenly for a few seconds right after you start it?
Are you losing a little bit of coolant each week?
If you've answered yes to the above questions, you could need-

A new head gasket!

What happens is that water leaks into a cylinder as the car cools, then has to be burned off when you start.

However, if there's no coolant loss, and the car runs well (or just evenly) as soon as it starts, then:

Valve guide seals could be the culprit. Or the guides themselves. A bit of oil leaks past, and has to be burned off. It causes little harm- BMW 2002's do this regularly. You'll also get a puff of smoke if you wind it out to 5500- 6k and then close the throttle- the vacuum in the engine will suck a bit of oil.

How to tell the difference? Sniff it! Really! Coolant will smell sweet, while oil will smell... well, like burnt oil!

If you have power brakes, it could be a leaky booster or master cylinder- but that's REALLY unlikely on a 122, as almost none have vacuum- boosted brakes. Again, pretty common on an '02...

HTH,
Toby