VOIP is rapidly becoming a popular way for businesses and personal users alike to enjoy crystal clear calling services at a fraction of the cost of a traditional landline. VOIP, which stands for “voice over Internet protocol,” uses the Internet to manage business phone calls unlike a PBX phone system, which uses a traditional phone line. While cost is one of the main benefits, there are a number of reasons you should consider VOIP for your small business.
In practice, most businesses are simply handling this on a case-by-case basis since COVID is a temporary problem. Most home networks can handle the extra load as long as the employee makes sure that other latency-sensitive traffic, like gaming or video streaming, is kept to a minimum during the hours when they need to talk. If some home routers develop problems, IT staff simply build a queue and handle those one at a time. Sometimes they'll be able to access the router remotely with the employee's permission, sometimes they'll have to walk that employee through configuration steps to fix the problem. Sometimes the employee will just have to live with it unless the company springs for a new router or a higher bandwidth tier from the employee's ISP.

Website: https://www.onsip.com/voip-resources/smb-tips/after-hours-voicemail-and-auto-attendant-greetings
Common business practice is within 24 business hours. Any extra messages or information you’d like clients to know. For example, if you are no longer accepting a particular insurance plan, the end of your voicemail greeting is a great place to convey that information.