A lot of the advise and guidance comes from people, who are very excited about their new hobby. But, they are still relative newcomers, and they just don't know all the facts. We have at least one contributor on the OB, who often writes partially misunderstood details.

There are many different factors to consider, whether you want to cut a spent Phalaenopsis spike - or not.

1. If you cut it, it can't produce an extension (most common in Phals with yellow flowers), or side branch (most common in the pinks).
2. Any such secondary blooming usually produces smaller flowers, but it tends to occur sooner than waiting a year for the next spike.
3. If you would like to small scale propagate the plant (via keiki paste or stem propagation), you need spikes to work with.
4. Cutting green tissue requires observing sterilization of the cutting tool. Cutting dried out material does not.
5. Esthetics (does it bother the observer to see old spikes without flowers?).

In other words, there is no right or wrong. On 1 & 2, I normally advise beginners to wait 4-6 months before cutting anything.

To go back to your original question, Cattleyas have no real rest period. They should be treated the same year round.

Out in the wild, the orchids aren't touched by anybody in general. Although - in our growing area, we do have the option to remove dried up flowers.

When flowers are dried enough - just like dried leaves - they can fall off by themselves. Although, sometimes, dried flowers might not fall off ----- but can be easily detached with hands (or something else - eg. cutters).

Also - when an orchid is no longer flowering (after the flowers have gone) ----- then the orchid's energy and resources can naturally be channeled else-where ------ instead of being used for flower development. So - in general - just maintain the usual care for the orchid ---- as in usual watering and fertilising and mag-cal schedule ----- and keeping an eye out for attacking organisms.

In my growing area, I usually don't even remove old dried flowers and stems. They usually stay there - unless I just decide to pull off dried flowers or cut dried up spikes after a long time - such as a year later heheh.