Sod's Law, only times I needed to jump start my own vechicles was when I didn't have me jump leades with me, so now make sure that I always carry them, and not had to jump my own vechicle since, usually end up jumping the diesel fork truck or tractor at work when some numpty on the night shift leaves the lights on,
Last winter the 2.5na got very slow to start, don't think I had to resort to jumping it, replaced battery (highest output one I could fit in) checked battery leads, connections, etc and then fitted a higher output alternator when standard one failed, awhile ago it got hard to start again so fitted new set of glow plugs, now starts o.k. even on frosty mornings. Must check the anti-freeze this weekend!