The length of the message counts too, so BT Mobile lets you store a maximum of 150 minutes at a time, with individual voicemails capped at seven minutes each. Some networks also limit individual voicemails to just two minutes.
It is necessary to record a personal message greeting after you have set up your voicemail number.

This article is about the second main type of greeting – the voicemail greeting. All businesses should have professional voicemail greetings at the company level (i.e. your general business number), department level (e.g. customer service), and employee level, where applicable. It’s important that each of these voicemail greetings align with the brand and personality of your company to ensure that every caller has a consistent experience. Let’s dive in!
You will be asked to delete your current Voicemail greeting. Click on the ‘Yes’ button that appears on the screen if you want to remove that. You can save your new recorded Voicemail greeting or can use the default recorded option. Wait and hear the new Voicemail greeting message that the instructions speak out. If you want to keep that recording as your Voicemail greeting, then save it. Or you can re-record the message to get a different greeting.