As an engineer, you should do your experimenting and playing with plug-ins in your off time or when mixing the song. During recording sessions, it’s best to put on some plug ins you know that will work for the time being and move forward. It can be a real vibe killer for an artist that is amped up and ready to record and you are trying out different plug-ins, effects etc. It’s one thing to adjust the mic or maybe swap out a mic if it isn’t working for the singer’s voice, but everything that is post processing like plug-ins, can wait.
One thing you can do is save a vocal recording plug-in template that you can use for every session. Then it’s very simple. Just import those settings in 30 seconds and you are ready to record with a nice sounding vocal plug-in chain in tact. In Pro Tools you would do this by creating a new session, importing some vocals, mixing the vocals with plug ins like eq,compression, and reverb, and then saving the session’s name as “vocal recording template” or something. Then when you go to record you next client, just hit Shift + Option + I. This will allow you to import the session data from your template. Unselect import audio so you only import the channels with plug-ins.