I think most of the advice you'll get here is that bricks are overrated for specific training benefit as opposed to a higher-quality bike-only or run-only workout. I found them helpful mostly as a matter of simple logistics ~ it's usually easier schedule-wise to just tack a short run onto the end of a ride than it is to go home, clean up, and then extract myself from the home scene again later for a separate run.

The one significant exception is trying to dial in nutrition plans/tolerance for long-course racing; otherwise it's hard to simulate how your gut will react to fueling on the run after 4-5 hours (or more) of sustained effort.

You'll hear a wide range of views on here about bricks, their importance, and specific protocol. But my general advice is, like everything else, get more specific as you get closer to the race. Away from race season, maybe one easy run off the bike per week. But most of your key bike and run sessions should be separate, so that their quality can be maintained.
As you get closer to race season, you might want to up this to ~2 brick sessions per week. Close to race season, these bricks should be your key sessions, and probably ought to include race-pace work on both the bike and run.
Multi-bricks can be good sessions, especially for short-course and draft-legal racing, but aren't necessary.

I did one the other night in the basement because I was time crunched and didn't fill like doing a straight bike or straight run.

Warmed up 10minutes on the bike, picked up the pace to HIM wattage for 10 minutes then ran 3k. I did this 3 times at ideal HIM power and pace. I've done 10' bike and 5' runs 4-6 times before when I was doing shorter stuff.

May not be the best 'quality' workout as some would say but it mixes it up a bit and keeps things interesting. I felt pretty good during and will probably keep it going for the next 4 weeks before my HIM at the end of May.


Hope this helps and good luck.