I have a fair amount of engines. It started getting hairy a few years back as I got more engines in different scales. That compounded as I did my own upgrades and board swaps in each. I found an easy solution at the time was to have 2 separate DCS systems. One for O scale and one for G. That gave me 2X more addresses. Whenever winter arrives, both are in the basement and started getting mixed together. Even worse I sold a TIU off and got 2 new ones. I did not do well in adding each to my systems even though I have Barry's book.
Adding a new single WIFI system into the mix started my troubles once again. It didn't hurt at first as I only used it for O scale 2 rail. Recently a G scale Big Boy arrived and I thought it would be much easier to use the app to run it with the smoking whistle. Our grandson prefers to run everything with the phone. That really messed up my previous solution of having 2 separate systems. My laziness about engine adds to the app without consideration for the remotes has bit me deeply. That phone app now has all different engines added without regard to keeping the original addresses in each engine let alone which system each belonged to.
Last night the grandkids wanted to run my Alleghenies. They had run recently so I figured it would be easy. My signal is back strong again after a recent battle over that. Yet neither the phone nor the remote would comply. As I went thru my engine lists in my 3 different remotes and the phone app I realized just how bad the situation now has become. Keep in mind I have two loops of O scale 2 rail, a 3 rail loop, and my indoor and 2 outdoor G scale loops. That's 3 remotes, four TIUs, a phone and a pad using the DCS app.
Engines have been added to whatever the choice of control for that day was and addresses are so messed up that I couldn't even find one of the Alleghenies listed in anything. The other one would not respond to it's address #5 and finally responded to G scale Big Boy address #2 after repeated attempts to control it. There are many other messed up engine address assignments that need to be fixed to list here.
SO...... the only thing I believe I can do now to fix this mess is to start from scratch and be more methodical with address assignment. Maybe a large dry erase board with addresses 1 thru 99 and even the TIU that was last associated with each engine???? Well 2 of them for O scale and G scale each! I need something like this as I keep buying and selling engines.
I don't know how the clubs keep anything straight. I have read some of their posts. I didn't apply anything to myself thinking I am just one person using all this. "I can keep it straight!!" 
Wait until I start buying HO scale too......
