I always have a hard time to decide if I should use a counter spell in a given situation and one step earlier if I should save enough mana for a counter spell this round.
I am currently facing this problem with my variation of Solar Flare. The main idea of this deck is to stall the game for at least 5 to 6 rounds while building up your graveyard and overpower the opponent with fat creatures afterwards when the fifth or sixth land is out there.
My counter spell of choice is Mana Leak. My dilemma is, that I usually want to use it early in the game, because it is harder for my opponent to pay the additional mana cost and my plan is to stall him anyway in the beginning. On the downside I have used my counter spells often before the real threats are out there and my opponent feels comfortable in the middle to end game because he knows that it is unlikely that I have any more counter spells available. I also do not want to use my counter spells after round 5, because I usually need my mana in those rounds to pump out and resurrect creatures. Without any ramps in this deck I have no flexibility to save up mana each turn instead of playing my creatures.
What is the expert opinion on that dilemma? How do I decide when to use my counter spells? Can I even formulate such a strategy without knowing the deck of my opponent well?