Lost the freon in April suddenly and then lost it again in July. Why

What is your question?

I have had this car since 98 and the air conditioning is what has gone out. I have replaced a compressor in 1999 and in 2006 I had to replace everything on both sides of the air (the drivers side and passengers side). The car has been used strictly for highway miles (200 daily) until two years ago. Oil changed every 3000 miles. Engine runs smoothly and has no problems with it.