A: Most vapors will change a personal vaporizer coil between every 1 to 4 weeks of usage. A general estimate would be 2 weeks, but you should always monitor the taste to look for signs that the coil needs replacement.
A: As you unscrew the top to fill it and the coil can loosen from the base. If tank is still leaking after tightening the coil, remove the coil and check the rubber seals. If these are damaged, new seals will be necessary to stop leaking.