Galaxy Websites
It all comes down to, how many errors are you willing to accept?
Your website should look great and it should be coded to the standards set by the Web Consortium (the standards people), but less than one percent of websites ever reach that level. How do you get to that level? Hire someone that produces and has produced all their websites to the same high-quality standards. The standards published by the Web Consortium (W3C.org) are the guidelines to follow to achieve that level.
What are the chances of chosing a web developer that knows the standards? Less than 1% of people that call themselves web developers validate their work. That means there is a 99% chance that you will choose someone that will not develop your website to the standards. I produce a 100% error-free validated websites using the W3C.org validation service (the group that issues the web standards). The few web developers that validate their work get to display this symbol on a page that has passed validation:
