The combination here is what Euwe called a break-up combination meaning it breaks up the opponent's King's position and the main line leads to mate. Euwe points out that before playing such a combination one must compare the relative value of the material that is available both before and after. You need to make sure that the remaining material (and/or position) is favorable!
Euwe gives some guidelines to take into consideration before embarking on a double B sacrifice:
1-One R must be immediately available
2-The enemy must not have a defensive resource
3-The K can't escape via the Bishop's file
4-Refusal of the second B sacrifice must have serious consequences
5-If the combination does not lead to mate then the material situation must be favorable.
Once you have determined all five criteria are met, then the sacrifice of both B's is sound and it's safe to embark upon it. Simple! The route most of us would take is even more simple...just play the sacrifice (assuming we even saw the possibility) and hope for the best...after all, "they" say chess is 99 percent tactics.