Welcome to TTF!
It's like anything else........if what you have serves your purposes, then is there the need for the 'latest and greatest'? Each succeeding map update for an area contains new roads, corrections for old mistakes, newer pois and often new features (Advanced Lane Guidance, etc.)
Is there a significant different between, say, a version 820 map and a version 830 map for a specific area? Perhaps, not so much. But for a version 7x map and the same version 830 map, probably a great deal.
You hear about people who have issues with a product in forums such as this much more than the multitude of people who don't have problems. That's the nature of places like this.