Sometimes 'unchanging' is used metaphorically to express reliability or dependability. His unchanging dedication to his work impressed his bosses.
Pro Tip 2/3
Timelessness
'Unchanging' often indicates something that remains the same over time, suggesting a static condition. The old town has an unchanging charm, just like it was decades ago.
Pro Tip 3/3
Not Absolute
Even if something is described as 'unchanging', exceptions or changes in different contexts are possible. The unchanging cycle of seasons was disrupted by climate change.