In Quality & Reliability Engineering, there is the term 'Mean Time Between Failures' (MTBF). It's a formula that mathematically determines the statistical probability of a system or component failure, and the time frame of that failure.
One of the key variables in this equation is the number of parts used in a system. Effectively, the formula can show that as you add more parts, the system reliability decreases, and the MTBF decreases. More parts equals more failures. Henry knew this very well.
I like gauges anyway. However, the failure of a gauge could cause a problem...for example: an oil line could fail between the engine and the oil pressure gauge, potentially squirting hot oil in your lap.
I took some steps to mitigate the lower MTBF created by the addition of gauges. In the case of the oil pressure gauge, I made sure to use only top quality materials in the lines, fittings, and clamps. Also, I made certain that the lines are routed and secured to prevent chaffing and vibration (stress fatigue cracks). Also, I added a shut-off valve at the engine block so that the entire oil pressure gauge system can be locked out, but the motor can continue to run. Lastly, the gauge and lines are periodically visually inspected.
Did these mitigations eliminate the posibility of a failure? No, but it did, mathematically anyway, increase the MTBF. Only time will confirm the expected results.