Is it true guppies are hard to keep alive?

Is it true guppies are hard to keep alive ? I just seen posts about how hard they are to keep alive and how they always die and you have to quarantine them before . Do you need to quarantine any fish you put in ? Is this true ? Was it probably just how they did it / their parameters? You’re advice on guppies and keeping them ? Should I reconsider what fish I’m getting ? Advice on anything is appreciated .