My kitchen sink is leaking at the top of the drain pipe. It looks like there is a rubber gasket where the sink attaches to the piping. Do I need to replace the gasket?

Is it the tail piece or the basket flange leaking? See if you can tighten the nut for the basket fitting. If it is the tail piece connection, try and tighten that nut. If that doesn't work, you may be able to unscrew the nut, silicone the washer and retighten. If necessary, you will have to disassemble and start over.

Do you have a garbage disposal? Back to you, Tom