Offgrid power can be extremely reliable. I reckon my own supply has been more reliable [over more than 30 years] than a grid system would have been for the same period. [It's certainly been cheaper, though that's another story]. It's probably a good idea to design system with some form of back-up that can keep your lights and fridge going if, for example, your inverter was to fail. Most of the parts of a solar system aren't likely to give you a sudden, surprise failure. Batteries and panels rarely fail unless they're mistreated. Inverters and other electronic gadgets can fail without warning but again, the better quality stuff rarely fails.
Primary system: .8KW Trina panels; Plasmatronics PL40; 1,000Ah VRLA 12X2V battery bank; 1.7KW Selectronic inverter
Veteran system, semi retired: 6 X 55W Solarex 12V panels; Fangpusun CC; 6 X 2V, 35 year old 550Ah lead acid flooded cell batteries.