Very true, and I do. However in actuality, the vast majority of surge suppressors do very little to protect sensitive electronics from small surges which are what most sensitive devices are damaged by. If you check the actual ratings of surge suppressors, their clamping voltages are fairly high and usually really only protect against catastrophic surges such as lightning strikes etc. Plus, many electronics can also be damaged by bursts of “SAGS” as well as spikes, and suppressors can do absolutely nothing about them. The only way to REALLY protect is with some type of uninterruptible power supply such as people use with computers, but it’s pretty rare to use one on a water heater. Those can condition the incoming line to remove all deviations. True, something is always better than nothing. I was mainly curious if anyone had any idea if one or the other, in general, tends to be more reliable over their lifetime. I’m sure standard/mechanical ones do fail at times, but it seems like it’s very rare. I’m not familiar at all with the digital type on water heaters, I just know that on most appliances, things like that tend to be more prone to failure and can be quite expensive to replace. Probably no real statistics exist to be able to ascertain an accurate answer.