Further the Dennis Knutson's comment, a program design maxim is the
'Black Box' approach. One should develop modules which isolate
functionality in a 'black box'.
You then use these modules at a higher level.
Anyway my own rules of thumb are: -
1) One screen height and no more than two screen
widths for diagrams.
2) Isolate functionality and modularise using SUB Vi's
3) If you exceed 1 then proceed and implement 2
If you take a look at the first example, what you will see is an
approach which creates 5 bars and controls them - from a beautiful use
of the inbuilt functions. All this is done in a quarter screen!
When I first started with Labview I sometimes 'Spawned' modules that
look like yours (screens were smaller then). I learnt quickly to start
fresh. I know that 5 years down the line, maintaining the code will be
almost impossible as it will take longer to understand to amend / fix
than to re-write.