Without it dropping?

Depends on your line quality, my old 2600 & 2820 never dropped on a good quality BT ADSL2 line. Can't speak for recent Draytek products though as I don't use them any more.

I've had connections for days or weeks, but there are many factors affecting this such as overnight maintenance etc... It's not really a useful question/measure ISTM!

Varies. For a short while wan1 on my 2920 reset every 24 hours while wan2 carried on. It's now gone 126 hours since I last restarted it.

Currently: -

2820#1: fw: 3.3.4.1_232201, system uptime: 984h, wan2 uptime: 849h (FTTC)
2820#2: fw: 3.3.4.1_232201, system uptime: 672h, wan2 uptime: 483h (FTTC)
2800: fw: 2.8.2, system uptime: 503h, wan uptime: 498h (ADSL2)

The 2800 was last rebooted manually in an attempt to fix a problem that turned out to be nothing to do with the router. 2820#2 is usually rebooted when the user gets a problem and reboots everything in site before discovering that the fault is actually windows on his laptop. 2820#1 is my own router and is usually rebooted when, after a long period of time, it looses track of some UDP VOIP nat sessions and will not allow some voip connections from * server.

I've had over 1000hrs on my ADSL1 line... And probably would have many times over but I sometimes do manual reboots for various reasons (not neccessarily because the router needs a reboot).

To be fair while my line stats are superb it is a testament to the router for going so long without cocking up! Don't think you would see 1000hrs on belkin or netgear products.