"When I was a child, people used to talk about what would happen by the year 02000. For the next thirty years they kept talking about what would happen by the year 02000, and now no one mentions a future date at all. The future has been shrinking by one year per year for my entire life." - Stewart Brand
Near futures: You can reasonably expect to live through them. Next 30 years till 2050. Becoming impossible to write as reality keeps overtaking the story.
Medium futures: You expect your kids to live through them. 30-60 years. The second half of this century looks ... interesting. LtoG non-linearity.
Long futures: 22nd Century onwards. All bets are off because there's a singularity between here and there.
2050. 32 years and counting. Remember 1986?