They (as with many others) can become troublesome once the coil wick gets saturated. The RBA can reduce the leaks somewhat by using more cotton in the build. I can build, go to vape and its like a tap has opened. Kind of wears thin if its bought juice(not cheap!). Still wears thin with DIY juice to, not to mention oil drips on your T shirt. Now using a higher ohm coil(only small on the kanger so amount of wick to feed through the coil is limited). Just with that set up, i cut longer, so once twisted the end, feed through then work back forth untwisting the cotton twist used to feed through. Normally you cut about level with the base or a little past. I tend to cut a little longer. On this (been a few years so going off memory here). You can soak wick which makes it easier to position, aim both wick ends up vertical, fit cap over, then tuck in/down to cover the juice holes. The only way it can leak is through the juice holes(or O ring). So packing out there(not too much as this can stop the juice, too little floods and spits). It is a little trial error, once done it is easier of course to remember next time. Coils them selves, once(juice dependent as darker juice gunks up coils/wicks faster than lighter coloured juice) should last a year! or more. Trim wick to remove, carefully pull out, if its tight it can bend/move coil and end up shorting. So always worth double checking with a small screw driver through, the coil is nicely positioned. Heat up coil till it glows, now one method is glow, release power button and under a running cold water tap. It comes up like new, flip side, can shorten life with the shock. So now i just glow, release power and blow it a few times. Comes up like new, ready for the fresh new wick and repeat. Depending on juice, it might be 3 weeks till next wick change.................or 3 days if a darker juice like a vanilla custard(very nice but gunks up fast).
This is where when RBA are used instead of ready made coils, reading up and actually seeing the base(youtube is super useful) is important. How much room, the design, be it trapping the coil under crappy screw heads, or nice little grub screws. Different designs, different amount of room all can make the build a pleasure or pita! Nothing worse than fighting and faffing for 10 mins to perfect due to being awkward, for it to flash up short or 9.99...............That can grow old fast. The zeus at the moment takes just a couple of minutes to swap out the wicks. For coil/s changing, add a couple more mins with trimming the legs and positioning.