How to detect surges in the main AC
Your appliance failures may well not be maians spike related.
Fitting surge suppressors to your outlets where expensive equipment is used sounds like an extremely good idea. These can be relatively cheap and a DIY solution is to use MOVs which are as good as many cheaper commercial offerings.

Below is a circuit and description from patent GB2231672
This is &quot;a bit basic&quot; but could potentially do an OK job of doing what you want.

A detector for detecting spikes on a mains electricity supply and for counting the number of spikes occurring during a period of time includes a zener diode (Z2, Z3) connected in series with a resistor (R4) and a counter (IC1) having an input connected across the resistor.
The zener diode and resistor are connected in series to the mains supply and the zener diode has a breakdown voltage of a magnitude such that under normal conditions it does not breakdown but upon occurrence of a spike in excess of a predetermined magnitude the zener diode breaks down and provides an input to the counter.



http://worldwide.espacenet.com/espacenetImage.jpg?KC=A&amp;CC=GB&amp;FT=D&amp;NR=2231672A&amp;date=19901121&amp;locale=en_EP&amp;flavour=firstPageClipping

This interesting combination circuit from here detects spikes in a similar manner to above but also adds &quot;flutter&quot; and noise&quot;. They drive LEDs but you could add a counter or other monitor. Note that unisolated connections to mains can kill with ease.