You didn't say what routings these flights are. Domestic or international. There are often non-refundable tickets with relatively small or no change fees. Thee tickets can be exchanged for a new ticket on any routing the airline flies, not just the same routing that was originally booked. Just because trips gets cancelled is not a good reason to avoid nonrefundable tickets.

Also, although most trip insurance policies cover cancelling only because of medical issues, there are some that allow you to cancel for any reason.

Both of the above would, in many cases, be much less expensive than waiting until the last minute. As stated above, last minute nonrefundable tickets often do not save very much over refundable tickets and in fact, also as stated above, are often not available.