Stable income: Somewhat stable

Washing cars as a side hustle can provide a moderately stable income stream for most people. Based on online sources and general observations, individuals can earn a decent baseline income, but there may be fluctuations in earnings from month to month. While some months may be predictable, others could be less so. I'd rate it a 2 out of 3 because there is a possibility of earning consistently, but the income can still be unreliable at times.