Were no man has been, well almost (Phoenix)

I thought the Spirit Mars Rover was stuck in some soft soil, apparently either they were able to find some solid ground or it doesn't really matter. This is a shot of the mound informally known as 'Von Braun'. The rover is on its way there for the usual investigative work it was sent to Mars for.

Now here's some cheese for thought; How long is a Sol in Earth time? and wouldn't time be different on Mars, as minutes and seconds are based on the size of the Earth, its rotation and speed? On Earth a day is 24.25 hours. A Sol in Earth measures is 24 hours 39 minutes 35.244 seconds. Time itself would be universal, but the units would be different based on the planet you are on. Thinking about that brings to light, how would you measure a Lunar day? And say you were born on Mars; the year is longer since it takes longer to orbit the Sun, so your life expectancy on Mars would be a smaller number but not any shorter than it is on Earth. If interplanetary/galactic exploration is to continue would it be wise to have a "non-Earth based time measure?
I do suggest reading this for more information, but as it is Wikopedia leave room for false information. It is a very interesting read.