Leonard Nimoy died on Friday at the age of 83. He had been suffering from chronic obstructive pulmonary disease (COPD), a disease diagnosed after decades of smoking. 

After announcing his illness in early 2014, Nimoy dedicated himself to warning others not to start smoking and to helping current smokers quit. 

He would often tweet about the struggles involved in living with COPD.

Nimoy quit smoking for good in 1984, but had struggled to kick the habit.

He let everyone know that that the struggle is worth it.

And gave hints to those trying to quit.

As well as encouragement. 

He even snuck a no-smoking message into Star Trek IV (which he directed).

Quit smoking image from Star Trek IV

He warned non-smokers not to start.

And seeing others give up tobacco because of his message was a source of happiness for him.

According to the World Health Organization, more than 3 million people died of COPD in 2012. 

This was Nimoy's final tweet on the subject.