Stable income: Somewhat stable

Window cleaning can be a moderately stable side hustle for many people looking to earn additional income. Based on online research and general knowledge, individuals in this field typically experience decent baseline earnings, but there can be fluctuations in income due to factors like seasonality and competition. While some months may be more lucrative than others, the overall predictability is relatively stable for consistent work. Setup costs for window cleaning can range from $100 to $500, depending on equipment and marketing expenses. If your best friend quit their job to pursue window cleaning full-time, you might advise them that it's a manageable risk with potential for steady income. I'd rate it a 3 out of 5 because while it offers a decent baseline, it may not provide the same level of stability as a traditional job.