I don’t know why using significant figures correctly seems to be a problem. The rules are simple, and, as posted at Good Math, Bad Math for those of us who make our livings by measuring things, they are necessary:

The idea of significant figures is that when you’re doing experimental work, you’re taking measurements – and measurements always have a limited precision. The fact that your measurements – the inputs to any calculation or analysis that you do – have limited precision, means that the results of your calculations likewise have limited precision. Significant figures (or significant digits, or just “sigfigs” for short) are a method of tracking measurement precision, in a way that allows you to propagate your precision limits throughout your calculation.

So, just because your calculator or spreadsheet spits 10 digits out at you, it doesn’t mean you get to keep them. Your results can only have as much precision as your measurements.

Now, don’t get me started on units.