i accidentally left my lights on for 3 weeks straight

2011 ok

Lack of reading comprehension skills stood out to me, but I am an asshole.

Plenty of people veg under 24hr light cycles. Nothing to worry about. It’s good to keep spare timers around. They're cheap enough that you should have 2 for every one you use. These covered timeres are clutch if you have pets or kids who might bump the dial and offset your light time.

BN-LINK Compact Outdoor Mechanical 24 Hour Programmable Dual Outlet Timer - Plugin timer, Waterproof, Heavy Duty https://www.amazon.com/dp/B079N9FW5B/ref=cm_sw_r_cp_api_glt_i_RDK70TF69D5YHFHZNSQV

Gotta be one of the oldest threads I‘ve ever seen resurrected, congrats Keith! That said I’ve never heard of too much light (including weeks of 24/0) ever hurting a plant in veg.