Mean Time Between Failures (MTBF) is a common way of measuring the reliability of a product. We calculate MTBF based on Telcordia SR-332, Issue 3.
(25C Ambient / Ground Benign)
| Model | Options | Hours | Years | 
| Sonoma D12* | None | 269,000 | 31 | 
| Sonoma D12* | OCXO | 235,000 | 27 | 
| Sonoma D12* | Rubidium | 138,000 | 16 | 
| GPS Antenna | n/a | 163,000 | 18 | 
* MTBF for Sonoma N12 without a front-panel display is even better.
(25C Ambient / Ground Benign)
| Model | Options | Hours | Years | 
| Sonoma D12 | OCXO | 235,000 | 27 | 
| Sonoma D12 | Rubidium | 138,000 | 16 | 
| Meridian II | OCXO | 235,000 | 27 | 
| GPS Antenna | n/a | 163,000 | 18 | 
(25C Ambient / Ground Benign)
| Model | Options | Hours | Years | 
| Meridian II* | None | 265,000 | 30 | 
| Meridian II* | OCXO & four 10 MHz | 227,000 | 26 | 
| GPS Antenna | n/a | 163,000 | 18 | 
* MTBF for Tycho II without a front-panel display is even better.
(25C Ambient / Ground Benign)
| Model | Options | Hours | Years | 
| All models | None | 263,491 | 30 | 
| All models | Dual AC/AC | 197,660 | 23 | 
(25C Ambient / Ground Benign)
| Model | Options | Hours | Years | 
| All Ninja models | All options | 1,194,000 | 136 | 
| External AC/DC Power Supply | n/a | 710,000 | 81 | 
| GPS Antenna | n/a | 163,000 | 18 |