I haven't been to Mexico since 2008 but I'm about to book a flight from China. I'm an Australian citizen.
I would like to stay from around Christmas/New Year until about the start of Semana Santa (Holy Week). That's around 100 days so more than three months.
Wikipedia says Australians are still entitled to 180 day visa-free stays, as it was for my previous visits.
But I recall that in those days the immigration officials in Benito Juarez Airport routinely granted 90 day stays (in your passport? on your tourist card? I forget...) and did not ask you how long you wanted to stay before doing so. My Spanish is good enough to manage this by the way.
I once used a trick I heard about to write "180" in the form myself in the space the officer is supposed to fill in. At the time this did work but the officer was not totally impressed.
Does anyone know if the immigration officers now ask how long you intend to stay before just giving you 90 days, or whether Australians are now routinely just getting the 180 days, or whether a trick as mentioned is still offered as advice?