I use both methods. Since I check & double check the chamber before I squeeze the trigger & since I've carried Glocks for years & owned a Sigma it's just habit for me.

A word of advice - use something other than the tool in the grip for lowering the sear deactivator lever. Many have complained about wearing the little knob off of it. I normally use a pen or pencil, anything other than the tool.

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Former USN, Retired US Army