There are many answers to this question. The answer is “Yes” if you want all the features that come with IP telephony, which you don’t get with PSTN networks. Examples are Call Flip and Voice to Email. The answer is “No” if you don’t care about special VoIP features, other than using the Internet to make phone calls. The answer is also “No” if you use a software package and its computer user interface instead of a handset to make your calls. Skype is an example of a VoIP software package.