If you have a website called www.greatbuilders.com then it will look more professional if your potential clients see an email such as info@greatbuilders.com or something similar and not greatbuilders@hotmail.com when they are making an enquiry. It makes sense to separate out your customer correspondence from everyone else because they are so important.
You can easily have a more general email for dealing with suppliers and other matters. In fact you should have a separate email for non-sales correspondence.
The cost for a hosted and fully configured and managed email exclusive to you and your company is £5.00 per month.
When your email box is full all your old emails are saved in archive.