I would like to also add to what has been shared here... in that, the reason as to why we take vows. For some taking vows seems to be something "scary" as one associates vows with being a monk etc. Why are is one scared? Well, there could be many reasons but it all stems from one's wrong perceptions and a holding on to one's attachment in some way or another.
We could try to argue this statement but the fact remains, we are "afraid" because we think it is a cage not knowing that it is actually liberating. Excuse me for digressing, that is another topic altogether.
Back to why we actually take vows. One can argue but I do not do all these negative actions anyways so why should I take the vows? Well, to be honest, that is great if we think or know we dont but the thing is we do not generate merits this way. We need to tap into the merit field of the 3 jewels by making the vow/vows and holding this "promise". Case in point... a baby does not kill, does not harm, is not hurtful , etc etc... does the baby generate any merits? NO! Same goes for us...
I actually learnt this from a fellow Dharma friend who told me to take vegetarian vows. My initial refute was, "but excuse me, I have been a vegetarian for many years now, much longer than you have, so don't tell me what to do". When he explained to me why it was important to take a vow it all made sense.
Sometime ignorance is NOT bliss... it is actually quite the opposite...