It’s hard to give a general answer to this question. The short answer is “when your show is ready”. The first question I’ll ask you is, why do you need orchestrations right now? Have you staged your musical or had it performed in front of an audience? Has it been through a workshop and several readings with rewrites and revisions? Do you have more interest in your show other than friends and family? Is your script and score formatted and ready for the next plunge?
These are all good questions to ask before spending the time and money on orchestrations. There are several things to consider when making this decision.
Edits, rewrites, and changes are much easier when you are working from just a piano-vocal score. If you were to hire an orchestrator before the script and piano-vocal score is complete, then you risk having to change and rewrite not just a piano-vocal score but the instrument parts and conductor score as well. This can be very time-consuming and expensive.
Some writers use Logic Pro and GarageBand to create their own orchestrations, and while this is a great way to be involved with your show, it may not be practical for live performances. We recently worked on a show that had demo recordings with orchestrations, but they needed them transcribed to sheet music for a live pit to play. However, the amount of layered instruments in the demo recordings amounted to 50+ individual instruments. This is not practical. This will work if you're going to perform the musical with backing tracks. If you're looking for live players, this needs to be reworked. We ended up having to condense 50 instruments into 14 books to make the show functional in a live setting.
If the goal is licensing, then I recommend consulting with an orchestrator about the next steps. My recommendation is to wait until your show has had several readings and workshops before considering hiring an orchestrator or to wait until a producer will invest in your show and pay for orchestrations as part of your contract.
If you're unsure about what to do, you can always reach out and contact us and we can point you in the right direction.