Do I need a new welding guage?

Almost every time i replace tank, it leaks at the fittings. I check with soapy water and retighten if it leaks. Weeks it will hold pressure. I do not release pressure. The high pressure is in the regulator, low pressure on the hose is no big deal.
Way i see it, a leak is a leak. Gas isnt cheap and fixing the leak is putting money in your pocket.