Can you sing every note?
The most important question, and yet so often overlooked. I sang the Count's aria for years and with the stress of an audition I often struggled with what baritones often refer to as 'that %^&$ bottom A'. Coaches always said not to worry, because for one thing many top tier baritones did Count on the world's top stages with 'nothing down there', and therefore panels don't care about that as long as you have a stonking top F#. The thing is, if I fudge a note, regardless of whether the panel care (and despite what some coaches say, they might) - I do care, and it may put me off.
Same goes for coloratura. Don't be fooled by recordings or live performances of singers who have what I'd call 'approximate coloratura'. Just because they get away with it, doesn't mean you will in an audition. The truth is, with all these things, we need to set higher standards for ourselves as singers than what we're exposed to, especially in the polite British culture where coddling by teachers/coaches/music staff is a pleasant but not particularly constructive norm. If we don't expect more of ourselves then we're risking a decline in vocal standards across the board. But I was supposed to write about auditions...
Can you sing it any time day or night, with a 3-year-old at the piano?
The key to auditions is consistency, so make sure most of your rep is prepared so solidly that it is foolproof even at a 9am audition (yes, I've had one of those). You can have one aria that you only bring out when you feel the power flowing through you, though personally I prefer to stick to the solid stuff rather than vocal acrobatics I can't always nail. It's better to sing an immaculate Papageno or Masetto (so-called easy arias) than a pretty good Largo al factotum.
Is it controversial?
There is a reason most casting professionals recommend presenting standard repertoire. It gives them an instant frame of reference. From what you sing, they can extrapolate what roles you may be suitable for. Within standard repertoire, there are controversial arias - ones that can be sung in vastly different ways, about which everyone has strong opinions. This can refer to tempo, ornamentation, volume, character, etc. These are probably best avoided. If you take something to coaches and get the idea each coach wants it differently - find a new aria.
Do you care?
Why are you singing it? If it's just because someone told you it suits you, then don't bother. You need to enjoy singing the aria, otherwise how are the panel supposed to enjoy listening to you? Find joy in the singing, find something you care about and can identify with in the character. Don't take an aria just because you feel you should offer a Mozart/bel canto/German piece, for instance.
What does it show?
You want to send a clear main message - I can sing. The secondary message is - these are the things I can sing. Ideally you want to keep that second one as broad as possible while maintaining its clarity. I used to audition with Pelleas' tower scene, thinking it showed I could do French, difficult music and high singing. I was promptly told that all it shows is that I can sing Pelleas. That's not all that useful outside of a specific audition for the role. Then when putting together a 3-5 aria set, don't necessarily think each piece should show something different. They'll only hear one or two, and will want to look at your other offered options and be able to imagine how you'd sing them. If you offer 3 different fachs, they'll just be confused as to what jobs you're trying to go for.
Can you do the role now?
If not, probably don't bother offering the aria. There may be exceptions (specifically covers / young artist productions), but offering Father from Hansel and Gretel at the age of 25 can send the wrong message - namely 'this guy has no clue'.
Do you know it too well?
The danger with overly familiar rep is that it can become under-energised in terms of performance, or a bit vague musically. Make sure you tighten all the screws every now and again. It's also good for the soul to introduce a new aria into circulation once in a while.
Of course, this mostly applies to general auditions. If you're going for a specific role, take the appropriate aria, on copy if necessary, plus pieces that are complimentary to that role. Taking a Handel coloratura aria to a Marcello audition is like bringing a knife... you know.
Well, that's it from me on this subject for now. I'm assuming singers out there can figure out their own equivalents for all my baritone aria references, otherwise they probably need more help than I can provide in a blog. In closing - don't blindly follow advice from teachers/coaches, listen to your instrument (it'll let you know if you're not ready for something yet, as long as you're not blinded by arrogance), and set high standards for yourself.