With my broker IB, when I trade option spreads, if entered, all legs entered, if not, none. If place orders for each leg respectively, you might end up naked call or put because some legs might not get filled, which is risky, you definitely won't do that.
I forgot to mention - the risk you take in placing the orders individually vs. in a combo is virtually the same.
If you place a four-leg combo order on the market vs the equivalent four orders, you will end up with four individual orders
in both cases.
Your four orders will have varying states:
1) Pending fill
2) Expired and failed to fill
3) Expired and partially filled
4) Filled completely
5) I might have missed some other states depending on trading platform.
On any trading platform, you will still be responsible for handling all of these cases, and any combination of these cases with all of your option legs.
You should not be under the illusion that combos are a "safe" leg entry method. You can enter a "safe" combo and still somehow end up with a negative balance if the orders do not fill as expected. That is, unless you manage risk.
