24 hours is already quite good for downloading a torrent. Some torrents can take several days! And it's always good practice to keep it running a few days more to seed (return to the network what you've received), there are others also waiting to complete the file. Before leaving the swarm, try to have a ratio of 1.5 to 2.0.
You can start and stop the torrent without issue, i.e. you need to use the computer or bandwidth for something else.