5 to 10

[SOGOAK]

I'm excited. I have (2) sankes in my garage.  I ordered the valves and will get the cutting wheel, step drill, and pickups.  I have Beer Smith so I figure moving to 10 gallons should be doable.  I'll plan to split ferment so those are covered as are starters.

Other than taking a little longer to run off more wort, any other worries?

[MaltLicker]

Takes longer to get ten gallons up to a boil. 
Total water requirements are increased. 
Batch expenses increase proportionally.

But you make more beer.   

[UselessBrewing]

Congrats on the new sankes! I was excited to get mine also... I needed a Larger MT, more BTU, and more Propane in order to step up to 11G(5.5Gx2 fermenters) batches.

I think the biggest grain bill I've done was 39#'s of grain, Imagine trying to fit that in your current MT (I now have 2 MT's).
Bringing larger amounts of water up to boil uses more propane and if you use a higher BTU rated burner you also use more. I now have 2 propane tanks for beer making. I usually only go through about 1/2 but Just in case one goes empty before the boil is done, I can switch it out. In the new brewery I will be going off of Natural gas, which should bring the costs down.

I find that I switch. Sometimes I make 11G and sometimes I make 5.5.  It all depends on the beer, allotted brew time, and the demand. It's your hobby, do what you want to.

Cheers
Preston