Really up to you. Some recommend after you shoot it. Some say till it stops working.😂
Good practice would be after shooting. That way you can inspect everything as well and learn about your gun. Follow Glock lubrication instructions in your manual.
Maxxtech 9mm 115 gr. round nose FMJ is fine. It’s relatively clean and non corrosive.
I am from NJ. The following is from the NJ State FAQ
I’m not a police officer, are hollow points legal for me to possess?
Yes. They are legal for purchase and possess in your home or on land owned by you. They are legal to possess and use at a gun range. They are also legal to possess while traveling to and from such places. Ammunition lacking a hollow cavity at the tip, such as those with a polymer filling, are not considered to be hollow point ammunition. An example of this can be seen with the Hornady Critical Defense / Critical Duty, Cor-Bon PowRball / Glaser Safety Slug and Nosler Inc. Defense ammunition.
My range does not allow the use of HP. Only round nose brass FMJ is allowed. Check with your range before you buy......