I've traded spreads for many years and also scale out, but in a different way.
I may start with a fairly wide spread, or overlapping spreads - let's say on ES and we open a 2000/2040/2080 butterfly. The first part of a butterfly (2000/2040) might be worth $28 when I put it on. I will enter an order to move the 2000 to 2005 when I can get 4.50 for it...or sometimes 4.00 depending on a number of other factors. The upper half might be worth $-17 or so. I'll do the same there but in 10 point increments, taking the 2080 down to 2070 for $1. This continually compresses the spread and reduces risk while increasing profit potential.
Of course everything is capped because it's a spread. The theory here for me is to take profit when I get 80% to 90% of the max and remove potential losses when I can cover them for 10% to 20% of the max.
Three things that are crucial to this.
1) Your may need to add spreads as necessary when the market doesn't cooperate and this is just an example to make a point about scaling
2) If you do this, you need a broker with low commissions
3) Whether it's 80%, 90% whatever, you should find the number that makes you comfortable and pair it with spreads that also fit your personality in terms of risk etc...
Scaling out may be "inferior behavior" with some products and some strategies, but it's the key to profitability for what I do.