^You have to have 50 posts (it gives you Bluelighter status) in order to PM more than once every 180 minutes.
To contribute to the OP's post, luer lock is just basically a brand name for rigs with a easily detachable rig/barrel, used more for IV/IM/subcutaneous infusions in home care settings I think than something like an 29g/31g 50unit or 100unit rig that is designed for subcutaneous injection of insulin. So the premises -> conclusion of it is using the one's specified for their purpose, properly, it will help to prevent any type of issues from arising.
Not only should u only use the needle tip itself once with a luer lock type of kit, but honestly if i were u i would just buy the barrels themselves in bulk and use the barrel itself too only once per shot preperation... keeping them around with street dope after a shot its like the best environment ever for bacteria to grow. I mean, obviously its bad to shoot dope period, but if youre gonna do it then its best to minimize the harm you do to your body ... otherwise it turns into this fucked up self-abuse thing (at least it did for me).
It's a huge hassle but well worth it - don't let your dope usage make you hate yourself just because others look down upon it, there is nothing wrong with using in a safe manner to keep yourself well until you are psychologically at the right place to stop. It's not even a big deal if you never stop, at least, not to anyone but you, because it's your choice and ultimately your life decision to make! That's the beauty of this all. It is good that you're open minded to harm reduction, it shows that you are getting fed up with being sick and tired, and perhaps looking for ways out. This forum is a perfect outlet for me personally to channel that anxious energy into something good, by hopefully influencing and helping other individuals to ease and get through their own personal hardships.
Luer locks are good because a big thing that fucks up with the insulin needles is that when preparing/drawing up a shot from a cooker/spoon, even with a cotton it still scrapes the bottom of the spoon, i mean, you can prepare a non-needle tip scraped shot with , say, two seperate insulin syringes, one to filter/prepare and then backload it into the other one once its nice and good... and TBH insulin syringes are way easier and convenient to use than carrying the whole luer lock kit.
Look up Sterifilt, its a filter technique used in the UK/europe moreso than the USA, but its been shown to be just about as effective as a micron filter and its way more convenient, they are way cheaper, and they are also easily usable with a traditional store-bought insulin syringe.
It's technically a "source" but, i am linking this page purely so you can get some more information about sterifilts (its literally the first link that pops up when you google so i dont think it should be an issue, even though sources are against bl rules
good luck and all the best with your continued recovery