You don't ever need to use frontline.
Defender mites only eat larva and adult mites, then die off without food, however the mite eggs then hatch around 1-2 weeks later. What I find works is two treatments of Defender mites approx 1-2 weeks apart.
Well no of course not, there are alternatives but as frontline is what we use, and what we've found works best it's the only thing i'm going to advise people to use.
I'm not going to go around recommending things i've never tried and frontline is (that we've found so far) by far and away the best solution so it's therefore what I recommend.
Now i'm sure you wouldn't expect me to list every anti-mite produce on the market, so i'll just stick to recommending what I know.
Frontline works and works well.
Provent a mite (as mentioned by another poster) is a terrarium/substrate treatment and is not for use on the snake itself. Frontline does both, negate the nbeed to buy multiple products. We use frontline and water. Thats it. job done. By the time this chap has finshed he'll have spend hundreds removing mites from an average/small collection. It cost us £40 (2 bottles of frontline) to remove our last mite problem and thats over 100 snakes treated. in fact we've just used the remainder of that frontline to give the CF royals a once over and theres still some left.
By the time this guy has finished pissing about trying various cures he'll have spent £40 on defender mites (IIRC they were 15-20 a pop last time we tried them) a further £20 on provent a mite or whatever and then go knows what else!
Pop to the vets, £20 on frontline and he's probably sorted for this infestation and the next three too!
Peple struggle with the idea of mites being present BEFORE you can see them. Keep up with whatever your cvhosen treatment of choice every 3-5 days for a month AFTER you've seen your last mite and be very thorough when scrubbing vivs etc.