You should always use "service myservice start" instead of "/etc/init.d/myservice start". Running "/etc/init.d/myservice start" directly means the service ends up accidentally inheriting parts of your shell's state (environment variables, limits, current directory), which is a different environment from when the service is started at boot. The "service" command carefully cleans up most of the environment before running the script, making it much more similar to what will happen when it starts automatically on next boot.
And if you were used to "service myservice start", it now automatically forwards to "systemctl start myservice" when the /etc/init.d/myservice script does not exist, so it keeps working nearly the same after the transition to systemd.
You should always use "service myservice start" instead of "/etc/init.d/myservice start". Running "/etc/init.d/myservice start" directly means the service ends up accidentally inheriting parts of your shell's state (environment variables, limits, current directory), which is a different environment from when the service is started at boot. The "service" command carefully cleans up most of the environment before running the script, making it much more similar to what will happen when it starts automatically on next boot.
And if you were used to "service myservice start", it now automatically forwards to "systemctl start myservice" when the /etc/init.d/myservice script does not exist, so it keeps working nearly the same after the transition to systemd.