The best travel advice I can give mirrors a saying that is popular in real estate but instead of location, location, location, the words to live by are insurance, insurance, insurance!! No matter if you are booking through a travel agency, or a flight/ cruise directly every carrier offers insurance and if you say no you are simply tempting fate. Unless you are one of these miraculous lucky people who never get sick, have a death in the family, work crisis or experience a natural disaster. If this is the case I am green with envy. For the rest of us insurance is just a smart and relatively cheap (when you consider losing the entire cost of your trip) option when traveling domestic or internationally.
However, this advice is not something I recommend for plays. It is a little know fact (until now) that play tickets are non refundable but can be exchangeable. I have been noticing lately they option to add insurance for about $10 or so per ticket as a checkout option. I never use this option and when a few months ago despite my best efforts was too sick for the first time to attend a play, I found out theaters top secret- if you call the morning of another performance (not the one you are missing) you can exchange it for one happening that day. It is called past dating and you need to check the theater because not all but most allow for this as long as they have a seat available comparable to the one you paid for. Be prepared- you will need your original ticket to bring to the box office the day you are actually seeing the show, in which case they will exchange for a ticket to the new performance so that you can get in as tickets are scanned for entry.