What's the earliest in advance you've bought event tickets?

A year or so ago I took my son to Batman Live and we both thought it was pretty good.
In January of this year I got an e-mail for advance ticket sales for a similar Marvel Universe Live arena show so I bought a couple of good seats. The show isn’t till April…2016.
I hope he’s still interested in going when he’s 10.

I"ve bought tickets for events anywhere from a six months to a year in advance if the tickets go on sale early.

Examples: I bought tickets to see

Richard II at the Barbican in March 2013 for a date in mid December 2013.

Brian Wilson in London in September 2011; I bought the tickets almost a year in advance, and then had to hope that he’d still be up to the show!

A ticket to see Abel Gance’s Napoleon at the Southbank Centre;bought it almost a year in advance (although to be fair, the Southbank publishes its schedule almost a year in advance when you consider the new season calendar, &c).

Most recently: tickets for the Viking exhibition at the British Museum - entry time is a morning in the week of 7 April; bought them when they went on sale back last autumn.

I’ve been toying for about a month or so to buy tickets to see Buster Keaton’s The General with a live orchestra at the Southbank Centre; it’s not until April 2015. Ditto purchasing entry tickets for a music thing that just went on sale a few weeks ago for an event not being held until late November.

When I make these purchases, I make a note in my diary and put the tickets in the ‘safe spot’ – half the time I forget that I’ve done them and it’s a nice surprise to discover when the date gets closer!

For myself: I’m already booked to give a public talk early January 2015, and another in probably early spring (April-May) 2015.

I’d say six months to a year, which can bite you in the ass Big Time. I capitalized that because I bought Big Time Rush VIP tickets (through a charity site) and so enjoyed the experience I thought I would buy VIP tickets for their last 3 shows that tour: Reno, Sacramento, and Ontario (California, next to Rancho Cucamonga). All were cancelled at the last minute because it dawned on someone “Oh crap - it’s going to take us five days to get all our equipment to South America for that leg of the tour!” This was after of course I’d made all my hotel reservations and the rental car and airfare and whatever. I shrugged and said “Well a vacation’s a vacation.” and came away with nothing worse than a One Direction tattoo. [“They won’t tattoo you if you’re drunk!” “This is RENO!”]