Why do i need to source bash profile every time on Mac

Stop adding the bash profile on your terminal every time you restart your mac computer.

I have a Mac Laptop and when I did stuff on the terminal with composer I would always have to refer to source bash. I finally found an article that allowed me to fix this issue. 

1. Run ps -p $$ at the command line to determine that you are, in fact, using a bash shell.
2. Realize that you are in zsh, which means you should be editing your profile in .zshrc.
3. Copy the offending lines from .bash_profile to .zsh

Source: https://stackoverflow.com/questions/15733508/why-do-i-need-to-source-bash-profile-every-time