when to pull the plug??

I have a compressor ...sears craftsman 33 Gal horizontal tank and it was new in 2003. My dad has the receipt from a black Friday special in 2003.

To put it lightly, I have used the crap out of it all these years and in the last few months I have noticed it sounds a little off when you first start it and then it straightens up and sounds ok after a few minutes of run time. It still functions well but it is slower to fill up now.

I recently borrowed my friends compressor and only then did I realize how much mine has slowed down and takes longer to fill up.

Is there a fix to lower the recovery time like when it was new or how long are these things supposed to last?