First of all, if you do not have VoIP phone system, you should transition out from local carrier to VoIP carrier. one of the best feature on the VoIP system is that you can have multiple lines with one single telephone number to accept many calls a long as you have enough bandwidth. Normally you would be charged $50/single line through your local carrier, plus additional charge for the usage. With VoIP, you would be paying little as $5--$10 on a single line and it can accept multiple calls. Now which way would you go? Hosted vs Premise VoIP server? Generally, Hosted service will cost $30 - $60 per handset per month. Whereas Premise solution, you would need to pay for the equipment. Generally premise solution will always beat any hosted solution if you look into long term. These days you can finance the equipment and your monthly cost will be about same as getting a hosted solution. Best of all, after you pay off your equipment, you will be paying much less for monthly charge vs hosted solution. There are many Voip solutions, but one of the vendor I recommend is Allworx. Allworx system has all the features you would need for any modern phone systems, Auto attendance, voice message to email, different call presence setting, different call routes. paging, PA, group handsets ring groups, call center, call analytics, difference time zone scheduling, offsite remote handset, call distribution, samrt phone apps, conference calls and multiples choices of handsets. more info at www.allworx.com
It's difficult to change anything, when things work and you get use to it. However, if you upgrade to new system and start enjoying the new modern features, you will be glad that you made the upgrade.