The difference between hoarding and collecting

With the research I have gathered so far I have noticed that there is quite a difference between people that hoard and people that collect. People that collect seem to want to look after their things and keep them pristine on their shelves or boxes whereas hoarders seem to live in clutter and rubbish. From watching a lot of these programmes about hoarders I've noticed that they tend to not want to invite people round to their houses and are ashamed or their mess. Which leads to them feeling very isolated but are extremely distressed when they are confronted with the prospect of having to part and discard the objects. Very obsessive and special condition. However people that collect are proud of their collections; some have made communities of friends who also have the same interests and hobby. Though collecting can work out a lot more expensive than hoarder spending money on trying to get the rarer items. Hoarders I have found to get attached to items and objects that can have very little or no value at all but find it harder to let go of in fear of the possibility that they might need it one day.