Like the rest of us, you probably don't like to get hassled with unwanted phone calls when you’re at home. You can also implement “enhanced call forwarding” to reroute and block the numbers that you specify, without the caller having any idea. You also can set up your phone to block international and directory assistance calls, so they don’t bother you at home. 
The security concerns of VoIP telephone systems are similar to those of other Internet-connected devices. This means that hackers with knowledge of VoIP vulnerabilities can perform denial-of-service attacks, harvest customer data, record conversations, and compromise voicemail messages. Compromised VoIP user account or session credentials may enable an attacker to incur substantial charges from third-party services, such as long-distance or international calling.
Once familiarized with VoIP services,  hone in on what these features can do for you and how to transition to the next level. First and foremost, is cost – a universal concern for anyone. Check the provider’s plans and pricing and be sure they’re the most cost efficient for your calling needs. There is also quality & reliability, portability, customer support, and a satisfaction guarantee; all key factors that may be clinchers or deal-breakers when going through the process.
Businesses need a number of phone features to improve their productivity and efficiency. The investment in achieving this with a fixed landline service is high, while many VoIP providers offer many of these features for free. Even for the more advanced services paid for, a VoIP service costs significantly less than a regular landline phone service.

Communication on the IP network is perceived as less reliable in contrast to the circuit-switched public telephone network because it does not provide a network-based mechanism to ensure that data packets are not lost, and are delivered in sequential order. It is a best-effort network without fundamental Quality of Service (QoS) guarantees. Voice, and all other data, travels in packets over IP networks with fixed maximum capacity. This system may be more prone to data loss in the presence of congestion[a] than traditional circuit switched systems; a circuit switched system of insufficient capacity will refuse new connections while carrying the remainder without impairment, while the quality of real-time data such as telephone conversations on packet-switched networks degrades dramatically.[16] Therefore, VoIP implementations may face problems with latency, packet loss, and jitter.[16][17]
A high speed Internet connection is required to "carry" your calls so if you have an Internet outage (or your ISP has an outage) then your phone service will not work. Internet services have improved significantly in the last few years and outages tend to be much less common than they use to be. Again, if you have a cell phone then this may not be an issue for you.
The only additional piece of equipment that you need is an Analog Telephone Adapter (also referred to as an ATA) that allows you to connect your existing telephone to your home Internet. This equipment is typically provided on a free lease basis from the home VoIP provider that you choose, or you can use you own device if you prefer. You can also use IP phone(s) instead of using the ATA with your existing analog phones. The sound quality is better but there is more up front cost as IP phones are more expensive than the ATA devices.