I was playing with somebody and they said I have to be careful about taking too long to serve, they said that from the point of the shuttlecock being held in front of the racket, it should be no more than 3 seconds between that and the shuttle being struck. Also(and this was a doubles match), I tend to do a backhand low serve by stroking the shuttle on serve rather than flicking it sharply, so that movement itself might take a second. + I spend maybe 2.5 seconds holding the shuttlecock in front of my racket
I checked the rules and I see he is wrong, as no such rule specifying seconds, exists, but the rule that does exist is still ambiguous
http://system.bwf.website/documents/folder_1_81/Regulations/Laws/Part II Section 1A - Laws of Badminton - June 2016 Revised 2.pdf
What is the minimum in time or behaviour that would cause an umpire to decide that it constituted undue delay?
Firstly, kindly refer to current laws, either here -
http://bit.ly/Laws2019, or from the main page here -
https://www.badmintoncentral.com/forums/index.php?threads/laws-of-badminton.134584/
The latter will be current, right kwun?
[Hint: it is not]
Secondly, an umpire can decide any delay by server to be undue delay. The one you mention here relates to being both, you and your opponent, in ready position. In terms of time, as an umpire, I could decide that you took too long (= undue delay), even if you took only 2 seconds from the time you picked the shuttle up at end of rally to delivering service, or 22 seconds.
In practice, the umpire will make a ruling of undue delay after having the pulse of the game, the rhythm, if you will, within reason. Of the many scenarios, lets consider you take spend 2.5 seconds in the set or ready position, and your opponent 5 seconds, from your very first serves. Both of you maintain that for a few points. And then, your opponent starts serving at 3 seconds. S/he does that again. Now the bar has been re-set. Now if that goes back to 5 seconds, it will adequate for the umpire to penalise with undue delay.
That your opponent will rebel and argue, is expected. No matter. The umpire will calmly and briefly explain just what is written above - you were serving faster, now you slowed; undue delay (simplest explanation is best).
Guess what?
If your opponent keeps arguing about that, the umpire has already set the stage. Your guess is correct as to what happens next.
You can do the vice versa thing, instead of opponent, it is you.
This type of undue delay is when both, the server and receiver are in ready position.
The other undue delay relates to completion of the backward movement of the racquet head.