Esteban Fernandezlopez says:

With the caveat that I’m not a vet, I think agility folks overestimate the impact of stopped contacts relative to jumping. They limit a-frames but don’t realize the majority of pounding a dog takes in the sport is on jumping. I think a lot of the physical strain will be from climbing the a-frame as opposed to stopping into a 2 on 2 off position at the bottom. For running contact work, I found that anywhere from 4-10 full dogwalks could be done in a session, more than 10 the dog is simply too fatigued to give the same effort or striding–this depends on the individual dog and how much rest you take between each repetition.

Yes, a lowered a-frame will be easier, and if I am several weeks away from the targeted agility trial/event, then that’s a good idea to use a lowered aframe, and then bring it back to normal height a week or two before the big event, or even sooner.

If you’re “cramming” for a big event the 2 weeks before, I think I’d probably keep it at regular height. I’d probably give at least 2 days completely off out of every 7 days, and I typically rest the dog the day before the event.

Esteban Fernandezlopez says:

At a national event, the biggest variation in judging calls are on contact obstacles. In general, judges will call the dogwalk most conservatively (often using a second judge in the finals) and the teeter most loosely.

If you have a “close” teeter performance where you’ve been called for it in the past, or you know from video review that your dog sometimes leaves the board before it hits the ground, you may run into a judge who calls them quite tightly at a national event. You may not know in advance but you can find out from fellow competitors, or watching the judge officiate a different height, or if you are later in the order, in your own height. Then you can be more conservative by helping the dog on the teeter rather than pushing ahead, for example.

Since you can’t always know in advance which judge will call teeters more tightly, I usually spend a trial or two before a big event holding my dog’s teeter a bit, and especially in the preliminary rounds before the final at the big event itself.