Windows Vista’s lifecycle comes to an end on April 11, 2017. This date is the end of extended support and end of life.1 We strongly recommend that you upgrade or replace any personal and business Windows Vista machines to Windows 10.
Mainstream support for Vista ended in April 2012. Mainstream support includes requests to change product design and features, non-security updates, and complimentary support. Extended support for Vista ends on April 11, 2017, which means there will no longer be security updates, any non-security updates, and paid support available.2
With no available updates (complimentary or paid), continuing to use Windows Vista after April 2017 could open you up to potential security risks.
1 https://support.microsoft.com/en-us/help/13853/windows-lifecycle-fact-sheet
2 https://support.microsoft.com/en-us/help/14085
Mainstream support ended for Windows 7 in January 2015, and extended support will end in January 2020. Windows 8 does not reach the end of mainstream support until January 2018, and Windows 10 in 2020.