Is there any reason to NOT use my ammo mods? How can I use them to greatest effect?

Question

So I've been running around with level 5 incendiary ammo turned on and it's giving me that warm feeling where I want to roast marshmallows over a smoking Reaper corpse and sing Row, Row, Row Your Boat with Spock.

Except when I actually want to use a different mod for a particular reason, is there any reason not to leave something like this turned on all the time? Will it eventually trigger some meter that will leave me vulnerable? Somehow deteriorate my weapons? Cost me credits? Kill my fish? Anything?

As a soldier I have access to Incendiary, Cryo and Disruptive Ammo options.

Do particular assault rifles work best with the ammo powers? Eg: Is rate of fire one of the best methods of determining it's effectiveness?

How can I use them to greatest effect in combat?

What are the strengths and drawbacks of each ammo type?

Answer 1

For the most part, nope. No reason not to always have an Ammo power activated.

An exception might be if you are specced into, for example, the final rank of Incendiary Ammo and the explosive effect would be inconvenient for some reason (Perhaps you're trying to snipe a target without blowing up a strategically placed explosive barrel or something.) Those situations should be pretty incredibly rare though.

Ammo Powers will never leave you vulnerable, they will not cost you credits, will not damage your weapons, and will not kill your fish. They will allow you to do more damage, apply useful debuffs, and, with upgrades, carry more rounds.