My A1200 had an uptime of around 3 months. Memory fragmentation eventually kills any long uptime.
I run a BBS. Or rather, I neglect a BBS. Its history is:
1995-2004 A1200. Running near continuously, only down for upgrades.
2004-2010 A4000. Continuously.
2010- WinUAE [1]. As an attempt to reduce power usage, noise and due to the gradual failure of the A4000. The image is a near identical 1:1 copy of the A4000, WinUAE's compatibility is pretty damn good.
[1] (WinUAE on WinXP on VMWare on Linux, accessed via Mac)