GT86 eats through batteries (getting about 2-3 years out of each one) so I've had to jump start it/trickle charge it and even bump start it by myself in a supermarket carpark at 3am with no one else around.
Started doing track days so I thought I'd learn some of the basics including basic servicing, wheel changes and brake pads, bulbs and other consumables I'd learned on older cars when they failed. Not had brakedown cover on any car for the last 12 years so figured if I do need it in the future I'll just pay the roadside price.
My old Civic Type-R used to munch through batteries with a similar rate to that. On a bit of a whim after one dying, I stuck a Yuasa battery in from Halfords (of all places) and it was rock solid, solved all my issues. Comes with 5 yr warranty usually as well, so if it doesn't work you can always claim.