A question about backing up vs. ghosting

I have Googled and read some, but advice here would be helpful. I know we should do backups, but I have found that when you try to restore there is usually something missing and they don't work. Will someone please tell me what is the best thing to do with my computer and hubby's, so in the event they can't boot up or something happens, I will have a complete copy that could be put onto another computer (or used to restore the pc). Is that what "ghosting" is? And if so what is the best software? I have seen free trials, but if one uses that and a time period runs out will it be useless for restoring? I have an external hard drive that I can use, and I also read about cloud storage.