It's been almost 1/2 a year since the launch of the nexus 2015, and a new one is coming. I want to know how often do android phones get supported with software updates until it becomes obsolete. It will ultimately decided if I should wait for this years model or buy last year's.
What version of Android did each phone in the Nexus line-up stop receiving updates?
Here is all the info, ordered by release date:
Device
Launch Version
Final Version
Lifespan
Nexus One
2.1
Eclair
2.3
Gingerbread
1y 1m
Nexus S
2.3.6 Gingerbread
4.1.2 Jelly Bean
0y 8m
Galaxy Nexus
4.0.4 Ice Cream Sandwich
4.3
Jelly Bean
1y 7m
Nexus 4
4.2.2 Jelly Bean
5.1.1 Lollipop
2y 6m
Nexus 7 (2012)
4.1.2 Jelly Bean
5.1.1 Lollipop
2y 8m
Nexus 10
4.2.2 Jelly Bean
5.1.1 Lollipop
2y 4m
Nexus 7 (2013)
4.3
Jelly Bean
current*
N/A: Launched 2013-07
Nexus 5
4.4
Kit Kat
current*
N/A: Launched 2013-10
Nexus 6
5.0
Lollipop
current*
N/A: Launched 2014-11
Nexus 9
5.0
Lollipop
current*
N/A: Launched 2014-11
Nexus Player
5.0
Lollipop
current*
N/A: Launched 2014-11
Nexus 5X
6.0.0 Marshmallow
current*
N/A: Launched 2015-09
Nexus 6P
6.0.0 Marshmallow
current*
N/A: Launched 2015-09
Pixel C
6.0.1 Marshmallow
current*
N/A: Launched 2015-12
*current version is 6.0.1 Marshmallow
So starting with the Nexus 4, devices have averaged 2.5 years between their release and final update. You should add on a few months to account for the fact that there was some time between their final updates and when that version was actually obsoleted by the next. And the 5 and 7(2013) have passed that mark, though they will probably not get Android N.
Sources:
Q & A