Subject: how many repetitions can a double mirror produce?

When I look in two mirrors facing one another, the image within the image is 
produced ad infinitum. But how many repetitions can a mirror really produce?

That is,since the repetitions get smaller and smaller at some point, the 
repetition get too small to see. But we can assume this mirror effect continues 
none the less. I guess at some point it gets to just one photon bouncing back 
and forth?  Is there a formula for this? (say, how many repetitions a square 
meter of mirror(s) will reproduce at a distance of a meter between them? 
 
 Also, I assume the reflections occur at the speed of light. This means that 
when one puts the mirrors facing one another, there is a small amount of time 
that occurs between the first large reflection and the final photon (or final-
whatever ad infinitum reflections happens). ?

 Thanks for any help with this, 

RC

Re: how many repetitions can a double mirror produce?