The need for calibration highly depends on the required levels of accuracy, reliability, documentation, and analytical importance of test results. For example, a hobbyist will likely have different needs in these areas than an organization involved in aerospace manufacturing.
If there is no real need, you can delay the calibration. Nextech Sales occasionally offers a rebate program to exchange your old gauge with a new one. It will often cost about the same, or in some cases less than sending the gauge in for calibration, and you get a new, calibrated unit with a full one-year warranty.