The understanding I have from what my spirit helpers have told me is that the guides we have are usually dedicated to us alone, and they have incarnated as human beings many times over themselves, so have a very close understanding of how it feels to be human. They are also usually people we are extremely close to in the spirit world, dear friends who have often incarnated with us here on Earth before. They help us with many things - from our emotional difficulties to loving advice to silly little details of our lives like reminding us we meant to buy some milk
. Your guide is the best friend you don't know you have.
Angels are more advanced spiritual beings who have usually not been human (if they have ever incarnated as physical beings, it was incredibly long ago from our perspective of time). While we tend to have particular angels who return to help us through multiple lifetimes, angels tend to help
everyone rather than being responsible for one person in particular (they are not bound by time or space and can attend to as many individuals at the same time as necessary). Rather than being involved in our Earthly matters as guides are, they act more as guardians who heal and protect us; an angel might intervene in the case of a life-threatening accident, for example.
We actually have a huge number of spirit helpers, though usually just one or two guides or angels will communicate in order not to overwhelm or confuse us! It's quite possible that more than one of yours might be speaking to you at the same time.