I used to offer 15min quickies but id get demoralising calls and texts it put me off.
Things like can you do 15mins  for ?20 instead of youre normal price?. Id just say if youre struggling financially just give your self releif its free. !

2 guys ive done 15 mins service with on this tour,to bulk my money up and they have both taken the piss!
never ever again..
the first was young and i explained i never usually do them,but it will only be 15mins,as i explained i have always end up going over time and it not fair..
he said "fine no worrys""im quick"
turned up,very young which i hate,jack the lad(not the problem though)had me in every poistion,do it like this, do it like that,yanking me all over the show..i knew a good 10-13 mins had gone i said "how do you want to finish"(which i  rarely say on full bookings)then he started taking ages..
i was getting so angry,he was struggling to come!!!
i said" thought you come easy"?anyway took him another 10 mins..piss take.
i know other girls would say times up,but i just got the image of him getting agressive,so had to just get on with it...
he left turned out he had 36 mins yes i timed!!
sent him a text saying "you were out of order"

that was yesterday,today an older guy rings asking for 15 mins,and i thought stupidly the guy yesterday was just bad luck!!
he comes in and the first thing he said is "ive took viagra"wtf
i explained its only 15 mins and hope he can come cus thats the time your getting..
he come just a few minutes after 15 mins,which is ok,but then wouldnt shut up!
obviously i got to be friendly,but hes waffeling getting ready really slow..
i even said got to make a call,ive gone over time,still been slow....
finally get him out of door and he still talking in bloody hallway!!!
i shut the door on him in the end.....
looked on my phone,he had been with me 41 minutes exacly......
 

I gave quickies a try a few years ago just to see what they were like and my experiences were very much like both of these. I think in the right set up, someone who is able to whip em in, whip em off, whip em on their way it'll probably work very well, but it doesn't suit me or how I operate and can so very easy be manipulated into taking up half an hour or more, plus all the rest in setting up the booking (I find the quickie enquiries often come from those who want to exchange umpteen texts, and make a right meal of things which kind of misses the whole point!).

I do 20 mins quickies and they go fine, can't even remember when it is that I had to go overtime for one. I price them at ?60, which I feel is fair. But I agree with you that one has to be firm about timekeeping. I'm no softie when if comes to it if I feel they're taking long to come, I say something long the lines "we've only got a few minutes left". Or if the time is up and they haven't come I may well say "What would you like to do, stay longer (aka pay more)?"

Every time I've done a quickie apart from in a parlour where the client would always shower first, the client has stunk and been lacking in hygiene (for longer bookings I rarely have had to make the client shower, they are usually clean on arrival), and most of the time end up going over the time and seem to actually want a longer booking but for less money

One quickie guy I had left a huge bottle of liquid MDMA in my flat, and I'm not too keen on clients who take or bring drugs with them, never had this happen on a longer booking, in general Ive found quickie guys to be worse clients all round, plus working from home I really dont want all the traffic it brings xx

My way of dealing with 15 mins is they can only book me within 15 mins