Nathan Matthews has been jailed for life with a minimum of 33 years for killing his stepsister Becky Watts.
Matthews, 28, was found guilty of murdering the 16-year-old in a sexually motivated plot before dismembering her body in the bath.
His girlfriend Shauna Hoare, who was found guilty of manslaughter, was jailed for 17 years.
The family of murdered teenager Becky Watts have described her as "beautiful, happy, funny, feisty, caring, loyal and witty."
A statement from Becky's mother Tanya Watts, grandmother Pat and brother Danny, said it had been painful to hear the 16-year-old described in court in negative terms as part of the trial of her killers.
Speaking via police family liaison officer Det Cons Liz Cousens, they said it was a statement they "never wanted to make".
The statement finished with a message to other parents, urging them to "cherish" the time they have with their children.
"Don't ignore or dismiss what they are trying to say. If they are feeling worried about something, take the time to listen to them," they said.
"Above all, cherish your children, as time with them is precious, and can be too short."
Nathan Matthews has been jailed for a minimum of 33 years for dismembering and murdering his stepsister Becky Watts.
The mother of murdered teenager Becky Watts reduced many in court to tears with a powerful victim impact statement.
Becky Watts' killers have "no right to walk God's green earth", her father has told Good Morning Britain.