If I come in after someone else has provided a proposal, estimate or any other kind of list for the equipment they're considering for a project, I may not do more than say "I can use the same equipment if you think you like it enough to consider moving forward immediately" or I may add some comments like "I don't know why they wanted to include a Sonos when that AVR already has MusicCast" (like I did recently). I had also gone to the house to look at any cable routes that might be needed and give my thoughts on the equipment list from the other dealer- since his friend had already recommended me and this client knows several other past clients (including one who married his ex-wife), he was half-sold on me doing it, but he had gone to the other dealer before I was mentioned.

Sometimes, it depends on who needs design work- if it's an existing client, I don't add as much but if it's a cold call, I'll tell them the cost depends on the complexity of the job and include that in the project unless they're using the design in the future and in that case, I won't be specific in the brands and models, but I will insist on using some kind of conduit for cable runs, to make sure the job doesn't become obsolete before it starts. I also include "This proposal is null and void after XX days".