Here is what the circular letter released by the Holy See in 1988, Paschale Solemnitatis, says regarding the altar of repose:
- For the reservation of the Blessed Sacrament, a place should be prepared and adorned in such a way as to be conducive to prayer and meditation; that sobriety appropriate to the liturgy of these days is enjoined, to the avoidance or suppression of all abuses. [55]
- The Blessed Sacrament should be reserved in a closed tabernacle or pyx. Under no circumstances may it be exposed in a monstrance.
The place where the tabernacle or pyx is situated must not be made to resemble a tomb, and the expression tomb is to be avoided: for the chapel of repose is not prepared so as to represent the Lord’s burial but for the custody of the eucharistic bread that will be distributed in communion on Good Friday.
- After the Mass of the Lord’s Supper, the faithful should be encouraged to spend a suitable period of time during the night in the church in adoration before the Blessed Sacrament that has been solemnly reserved. Where appropriate, this prolonged eucharistic adoration may be accompanied by the reading of some part of the gospel of Saint John (ch. 13-17).
From midnight onward, however, the adoration should be made without external solemnity, for the day of the Lord’s passion has begun. [62]
- After Mass, the altar should be stripped. It is fitting that any crosses in the church be covered with a red or purple veil, unless they have already been veiled on the Saturday before the fifth Sunday of Lent. Lamps should not be lit before the images of saints.
Unfortunately, there are some parishes in my diocese that still use the Monstrance. What I would like to do is give everyone a copy of this document. Maybe that might help, since, as far as I can tell, the document has not been abrogated and we are still obliged to obey it.
In our parish (and in a few others), the Altar of Repose is kept in the little room we use for Daily Mass and the adoration runs through midnight. Other parishes have it set up in the parish hall, but, many others do not follow the norms.
Let me explain why I know this. Every year, I have had the custom of visiting seven churches on Holy Thursday, with my first stop at my parish after our procession. Next, I go and visit six other churches. Mind you, I go to pray, not to inspect. However, it is rather disappointing to see what goes on throughout the rest of the city. I am going to amend my rounte this year, but, I never know what to expect.

The usual time for adoration to stop is midnight, though.
We used to have a seven-church bus tour when I was at the Cathedral. Our bishop, rector, deacon and I would participate. The bishop and I would ride the first bus, which was a trolley since I was the one with the route (and directions). It was a lot of fun because we would be praying as we rode along. The bishop would hop fro mbus to bus (there were three) and the rector and deacon would also switch off. Of course, the bishop wound up seeing some stuff without meaning to and corrections were made. It was kind of nice because all of a sudden, we would descend upon an empty church and surprise the pastor. Unfortunately, this custom has since been long gone.