I try to avoid it of course, but occasionally I used up the battery to the limit, but I never experienced a sudden drop even if it went down to 6% or even 4%. It was a rational decline all the way.
If I would use the phone continuously for the whole day browsing web pages and taking pictures for example, it wouldn’t last that day I suppose. I don’t want to imagine what playing demanding games would do to the battery 
…
With my non-power user average usage however it easily lasts a day and more, but I usually charge it at night.
Lacking better battery options, I would get me a powerbank otherwise.