Should the oil be topped up?

In order to avoid problems, the oil level should be checked regularly. A small quantity of the oil in circulation in the engine is burnt (an engine in good condition will consume between 0.2 and 0.5 litres of oil for every 1,000 kilometres), but top ups do not eliminate the need for regular oil changes. 
Consequently, it is normal for an engine to consume a small quantity of oil, that can be dealt with by small top ups between oil changes; however, the need for frequent top ups may be an indication of a mechanical problem (leaks, etc.).