Some factors contemplate are the era of the machine, the make, and optional safety features or anti-theft devices. Ask for the title and author and then their ideas and opinions. In fact, we don't grow into the full adult we is likely to be until mid to late 20's-if not later. http://chem-tech.com/__media__/js/netsoltrademark.php?d=Forum.Elaivizh.eu%2Findex.php%3Faction%3Dprofile%3Bu%3D310916