When to stop a bedtime rountine?

I have two beautiful monsters aged 4 (nearly) and 18 months.  From before they were born I was adiment that they would have a bedtime routine from the first night I put them to sleep.  Of course this was never going to work with a newborn (no matter how hard I tried) but I did keep on with it as much as I could until they got to an age where it did start to work.  I think I've got a very nice routine that works for both parents and the kids and in our house it looks like this:-

6:00pm                       Toast for super and a warm drink of Milk
6.15pm                       Mum and Dad both get them in the bath so they can have a splash
                                  together.
6:40pm ish                 Out the bath and into PJ's.  Goodnight kisses and hugs given to all 
                                    and then bed
7:00pm                       Into bed with 2 stories
7.20pm                       Finish stories then kisses and big light out and night lights on. 
                                   Gentle sing song for 5-10 minutes while children drift off.
7:30pm                      Mum and Dad downstairs for a drinky drink as beautiful children
                            sleep.I'm not saying for one second that it is this straight foward every night and of course you throw the add tantrum in there and the whole thing goes out the window.  The main point I want to make is that the kids know this is the routine so they know what is expected and it helps calm them and get them ready for a good nights sleep.  It is by no means set in stone and there have been many times when I've had the crapiest day with the kids and just want to get them to bed because they are screaming tired, so I do.  I skip the super if it was a late tea and I skip the bath but I always, always read them a story and have a sing song.

I am also a firm believer that you don't punish kids by sending them to bed early.  I don't understand what this achieves other than getting them to not like going to bed and making it harder for yourself when bed time comes around.

My question is how long do you keep a routine for?  Do they get too old for a routine?

I only ask as I have friends and family that believe I am moddy coddling them by keeping them in this routine.  A family member also has two children of a similar age.  We were round at their house one evening and it was time to put the kids to bed.  She had them go round and give Uncle Steve and Auntie Sue a kiss and cuddle night night and then she sent them off up stairs.  I was waiting for her to make her excuses and say she was just popping up to put them to bed but she didn't.  She literally sent them off up stairs on their own to put themselves into bed.  They went.  All by themselves they went.  No bath not story no nothing they just went up to bed. 

I shot Steve a look of "can you believe that?" and he shot me a look of "don't make a fuss!"
I was amazed that this worked as they did put themselves in bed and we didn't hear from them for the rest of the night but it just goes against everything in me.  Why would you not go up and have that kiss and cuddle as you tuck them in?  Why would you not read a bedtime story and listen as they filled in the best bits for you?

When I told this story to several friends some of them also said that I was setting myself up for a fall as the kids would expect this behaviour of me from now on.  They should be putting themselves to bed and reading themselves a story and settling themselves down.  I totally agree with this and would want them to be doing this later on but not just yet.  Little H is only 3 1/5! Am I being too much by keeping her in this routine? Should she be putting herself into bed by now?  It would be interesting to know people's thoughts on this as it just doesn't sit right with me and I do love the routine we have.

I also like the routine as it gives me one-on-one time with the kids and sometimes Little H just wants to chat about her day or something that is clearly on her mind and I don't want to take that opportunity away from her so I'm not keen to give the routine up just yet.

I know many people have different opinions on this type of things but I've come to the conclusion that I'm going to keep doing it for as long as my kids want and need me too.