You should consider performance before deciding whether or not to use threads.

In general, making a coroutine call has a longer path length than making a direct function call. Nevertheless, you should use threads when making calls to functions that have lengthy execution times, such as long calculations or communications and database access, so that VA Smalltalk remains responsive for other work.

For high-frequency calls to functions that perform only minimal processing, there is usually no incentive to use a separate thread.

See Programmer Reference for more information on using threads.