Yes always. You need to figure out what works for your horse - you don't want to leave your best jump in the warm up. And getting the timing right is a matter of practice.
A BS Trainer taught us to work from the number jumping - so doesn't matter if it is drawn order or not. As a general rule you want to jump the first cross pole 10 riders before you. And your last fence - however you structure that for your horse - 3 riders before. That only needs to alter if you are at a venue where you have to be in the chute 3 riders before in which case move it by one.
Before jumping you want to have a relaxed horse. A trot & canter on each rein at least. Some need more, some need less. We did have a BS pony for a while who would overheat massively in the warmup and so literally only walked around the showground before going in. But that is rare. For the warm up jumps as a basic plan you need a cross to start. Then an upright and an oxer. Again as a basic rule of thumb we aim for 4 - 6 efforts in the warm up unless the animal needs more / less. Always yell your intention to jump as you round the corner - helps other avoid you.
For the jump off or subsequent class we tend to keep to a walk, keeping the quarters warm with a sheet if cold. And 2 or 3 jumps only. Unless you've got one who needs to be fizzed up for the warm up.
My basic plan (which was given to me by a trainer years ago) is to warm up on the flat until the horse is in the bridle, relaxed and listening to me. Then I jump a cross, 2 uprights, 2 oxers and a final max height upright and leave it there, walking until I go in. This base plan is then varied for different horses - one of mine only walks around the showground until she's relaxed, canters a few circles in the warm up and then jumps one or two fences before going straight up to the ring - any more and she boils over. Another, I tend to finish on an oxer rather than an upright and may jump a couple more fences than in the base plan. What I have found, as someone who doesn't really like warmups, is that the base plan gives me something to work from and vary as required!
Shay - love your timing rule re 10 horses etc, I'm going to steal this!
Really depends on your horse! But for me I have a rough warm up plan and tend to go with how shes feeling on the day. She can be a bit of a stress head so I try to get on a good 20 -30 minutes before I go in and just walk round for about 15 minutes to get her lightly warmed up and relaxing. 10 - 15 minutes before I'm due in I start warming up properly - trot round for a few minutes then canter for a bit. I try not to overdo the jumpin but she does need enough to get 'in the zone'. So I like to do an upright and a spread a couple of times at a few different heights until I feel like shes ready (she never ever stops but can jump a bit flat in to start with in the ring if we're not warmed up enough). I think the most important thing for us though is keeping her going right until we go in. If I stand around waiting to go in for 5 minutes she switches off a bit and we're prone to having one of the first few fences in. Just before we can go in I try and have a quick canter round and one final jump then go straight in the ring and keep her moving. Also have a good canter and get your rhythm going round the ring before heading to the first jump!
I know what I want to feel from the horse before I go into the ring, and I know several different plans to get there. Which plan I choose depends on how the horse feels - you have to ride the horse you have on the day, and get the best out of it, rather than stick to a strict warm up routine that you've decided ahead of time.
I think it depends on the horse. For me my horse gets quite buzzy, and if worked up starts to rush. I keep any warm up short, sweet, forward and thinking.
I w/t/c on each rein jump 2 - 3 X poles, an upright then an oxer. Whole warm up is usually 20 minutes.
However this year I plan to try warming up, going back to the lorry for 15 minutes then coming back and doing a shorter warm up just before going in, to see if the 15 minute chill time takes a bit more of the edge off.
I have a stressy mare, so like MadEventer a key part is a long walk. I get her brain and body busy by doing shoulders-in, flexing, leg yielding, counterbending. Then a bit of trot until she gives a willing stretch, canter a loop or two, maybe a flying change. Jump a small vertical, larger vertical, class-height square oxer (usually end up screwing the distance to this off the right rein so often do it twice in that direction), and then because she's spooky drop it back to the large vertical and throw a scrim/sheet over it to let her jump something "scary"... I try to time it so she walks straight out from that into the class- sometimes I need to watch one more rider go to remember the course though!