Today many website owners find they have issues with spam or being hacked. This can really damage a website and the downtime can destroy the site. People find it hard to maintain a site and keep it up and running. The hosting provider will do all they can to keep your site up and running. However, they don't do a backup daily on your site. If you have an issue with your website, you'll need to rely on the hosting company to install their latest backup. This could mean data loss and information that was posted on the site before the last back up was performed.
Therefore, it is basically up to you to make a site backup to ensure that you can reinstall your site from a backup and lose the least amount of data as possible. If you do a site backup each evening and your site has been attacked, you can ask the hosting company to restore your website from your own backup.
When signing up with a hosting company, it is wise to find out how often the hosting company will make a backup of your website. This will give you a good idea of the current backup on your website. If the backups are made ever 5 days, you'll understand that your data restored to the site is 5 days old and you'll have a lot of work to do to fix or correct these problems. However, if you had a backup from the day before, the hosting company could use your personal backup to restore your website.