Here are some things to consider if you absolutely cannot be talked out of stopping altogether.
1) Trust your family more than yourself when it comes to your behavior and whether it's a problem.
2) At some point you are likely to encounter negative effects like appetite suppression and sleep deprivation (or the results of those things like paranoia). In an effort to not give up your cure for boredom you may be tempted to "self medicate" to compensate. Opiates, alcohol, and benzos are popular choices for that. DON'T DO IT. The answer is never more drugs, but less. Many a speed-freak found themselves accidently a junkie that way.
3) Testing is a fantastic idea, but if you are tight on cash, that is likely to go right out the window. You'll tell yourself "it's been OK so far, so it's probably good." If you catch a fentanyl-laced batch, that mistake might be fatal. Maybe have some narcan on hand and let whoever you are with know its there and how to use it in case of emergency. Fentanyl is potent, the little sample you test may have none in it, but what you put up your nose might. You bought it from a drug dealer, even if he knows fentanyl is in there (and he may not), it's unlikely to be evenly distributed.
4) Having lines drawn to act as "warning signs" for you is not as helpful as it might seem. I don't know who originally said it but, "The chains of addiction are too weak to be felt until they are too strong to be broken." Addiction will sweet-talk you into crossing any line you draw for yourself. It's slow and it's subtle. Don't be cocky.
NEVER EVER forget that you are playing with fire. Your judgement is effected even after you no longer feel high. You are gambling with your life and your health and cocaine is the casino. In the long run the house usually, if not always, wins.
Think carefully. Are you SURE you haven't ALREADY crossed one of your lines? Before you did it the first time, did you tell yourself that doing it every day would be acceptable? Has money you SHOULD HAVE spent on something or been saved ever gone to getting coke instead?
There are people who recreationally use coke, I know a few. None of them does it daily. Or even weekly. There are a lot of negative and serious consequences that are involved with using drugs and some of them affect the ones you love more than they affect you.
All it takes is to get arrested for possession or losing your job from a failed drug test to drastically alter your life for the worse, so don't forget those possible consequences as well.
Not all drugs are "bad". There aren't any drugs that are inherently good either. In my experience drugs like coke, crack, meth, opiates, and benzos have a nack for getting out of control before you have a chance to stop. I'd advise cutting back your usage before you drop the reigns if you want to keep coke part of your life without destroying it. Every once in a while see if you can arbitrarily stop for lets say a month or two. Simply just because. You might find you can't do it, or that you start telling yourself you'll try it next week, or tomorrow, but never TODAY.
I used to abuse drugs. I threw away everything I had. Several times. Don't get me wrong, I like drugs and I still use drugs, but I had to cut out all of the ones I mentioned in the previous paragraph to stop USE from becoming ABUSE and ruining my life yet again (at least SO FAR). I'm not saying that's the case with you, but I have been exactly where you are and ended up where I am... Please be careful. Please be safe. Don't ever drop your guard.
Good luck.
