hours wise only done fairly standard, although I have worked 16 days straight, without a day off.
Not quite the same as 7 days a week, start at 7am, get home (on days when you actually made it home) around 10pm, most weekends not making it home, from June 1998 until 24th Dec 1998 (as BT wanted their Y2K stuff completed before 1999)

. That was upgrading NT3.51 and NT4 servers, Netware 4.11, OS/2 Warp and MS-Mail to Y2K compliant versions, and rebuilding earlier versions to at least those standards.
That was hard work, yet immense fun, and a real challenge (realistically unachievable). Probably the most enjoyable time I've had in my career.
There were just 2 of us doing it for our area (East Anglia to Aldershot, inc North and North West London (and oddly, Stone Staffordshire and Doclands, not sure why we had those in our area)), and we PM'd everything. Only help we had was a secretary was provided, who'd send emails, and do all the admin/officetosser tasks.
I do recall, around November-ish, she sent us a load of spreadsheet graphs, and one stood out... ...a Windows domain with about 130 servers in, all that needed a complete rebuild, and the pie chart showed it clearly... ...none started! To this day, I'm still not quite sure how we did it, but shows what a close team (of 2, plus the admin girl who was purely office based) can achieve, and a vital life lesson (actually, lessons) learnt.
I passed out Christmas day.