I rarely do, but I will disagree with my colleague. It is true that it isn't used as much these days, but if you would like to use a quaich in your ceremony it is perfectly acceptable and there is a tradition that goes with it.

If you are being married in a church with communion (and if the celebrant allows it) you could use the quaich to share your first communion together. The quaich may then also be used for your first toast together. Should you use the quaich for your toast you will then pass the quaich to both families. You may choose to pass it to one representative of each family (usually the fathers) or you may choose to share it with all members of both families. My preference is for just the fathers as passing to all of the family members can be lengthy and distracting. At no time should the quaich be completely drained until the last person. (This is different than toasts at other events where the drinker specifically shows that they finished the whisky.) If you are passing the quaich to all family you would obviously not have one big enough to hold whisky for all. In this instance you would send an attendant with the bottle of whisky to keep the quaich topped up.

By the way if you have a family toast as well as a toast to the piper you will use a different quaich since you will want to keep the quaich you toasted with and not give it to the piper to take home.

Small quaichs are often given as groomsman gifts as well these days.