We’ve got an old trick back in M14 with the reprinting of Quicken, and a similar bag of fun with Savage Summoning. These spells allow you to turn less reactionary things like creature spells and Sorceries into any time spells like Instants.  First, a few quick things to cover: neither of these change your spell’s type. A Quickened Sorcery is still a Sorcery, NOT an Instant; as such, a Dispel or similar won’t be able to touch it. A Savagely Summoned creature does not actually HAVE the Flash ability, if anything were to care about that; the spells just let you cast them as though they did.

Now, onto the second part: These fun little spells only work on one thing each. Quicken doesn’t let you turn a hand full of Sorceries into an Instant barrage, nor does it ‘refund’ your increased spellslinging if your Sorcery gets countered, nor will Savage Summoning. The very very very next spell of the appropriate type that you cast in that turn will use up the ‘buff’, whether you want it to or not, whether it resolves or not! So make sure you pay attention to which spell you’re casting.