This is only really a viable option prior to launch, of if the probe is coasting and you have enough time.
If the probe is already near its destination, you have a very narrow window during which you can adjust its velocity for intercept.
If you delay too long you do not have enough deltaV to intercept, and either miss your target entirely, or end up in the wrong final orbit with no ability to correct your inclination or eccentricity to what your mission parameters call for. Then you've basically spent years to send a paperweight to Mars.
If the probe is already near its destination, you have a very narrow window during which you can adjust its velocity for intercept.
If you delay too long you do not have enough deltaV to intercept, and either miss your target entirely, or end up in the wrong final orbit with no ability to correct your inclination or eccentricity to what your mission parameters call for. Then you've basically spent years to send a paperweight to Mars.