Well, so far, every woman who sang Gypsy on Broadway came to some grief at some point with singing it 8 times a week. Merman burst a blood vessel, missed a few shows, and the keys were lowered upon her return. I've seen some postings on the net from people who saw Lansbury in tattered voice, but still managing to pull it off. Daly of course, is in famously bad shape on the cast recording. Even old ironsides, Betty Buckley, missed a week's worth of shows at Paper Mill. Peters, as I mentioned earlier, had two blow outs, one prior to opening and then immediately after, but then settled in and really had no incidents of losing her voice for the rest of the run of more than 400 performances.
So far so good with Patti, but if it happens to her, there's certainly a history of that role being a vocally taxing workout for the best of the best.
Begin at the beginning and go on till you come to the end: then stop.