For every programmer, designer and a company, if they are hosting their website then their main an primary concern is that there website should be active all the time. Not even in the business hours but during non-business hours too they want and demand their website should be live.

Though it doesn't depend on your hosting vendor but its connected directly to their servers on which your website is hosted. The hosting vendor will not be disturbing your website but the server on which your website is hosted may be.

There are few main reasons that have been noticed. These includes your server up-time, server resources that your website needs and 'where you are hosting your site and where you can viewing it.

Let's discuss these factors in detail:

1. What type of hosting you have: There are majorly two type of hosting services - Shared hosting and Virtual/Dedicated hosting/Private Hosting. In shared hosting your website is hosted on that server on which already there are few of more websites are hosted. The number of other websites may vary from 100- 200 or may go to 500. Again I must say that you don't need to bother other websites but it depends on your websites that how much server performance and resources it needs. On a shared server your website, if needs high resources, may get slow and even 'not responding'.
2. How much your vendor is reliable: Remember that hosting your site is a technical thing and errors can come on your way. Though again when you are using shared hosting and not managing your server then it becomes duty of your hosting vendor to update you for the downtime. The main thing in this concern is whether you are updated or not. 'GOODWILL' is not what is good for you but 'GOOD RESPONSE'.
3. How much you need: No one can't be sure whether your website is going to be a heavy one of a very light one before hosting it. Once your website is hosted you can get the data as to how much server resources are consumed by your website. Server resources includes your CPU usage, bandwidth usage and memory(RAM) needed. If you have heavy database on your website or if the visitors are high on your website then you may have to get shifted to Private Hosting(VPS/DEDICATED SERVERS).
4. Any updates: Being a programmer or a designer you will be doing some updates regularly on your website. These updates includes installing plugins or running scripts. Before doing such updates make sure that your server is ready to support it or not. Go through the requirements of your plugins and scripts before installing them.