Depends on the character I'm using.
With Samus, I like to be fairly adaptive/offensive with her, and it's usually me that brings the fight to the enemy with dash attacks, back-airs and grabs. But I usually won't pass up the opportunity to make use of my ranged abilites through a barrage of Super Missiles if it presents itself (Spamming I guess, though it's not a move I'll use forever), unless I know the person and the way they play, or just feel sporting enough to get some hand-to-hand going.
Marth's a mix. Offensive is the main way I play since closing the distance with ranged attackers is paramount, and air juggling is the chief tactic in my book. Spamming never really comes into play since I don't use any attacks over and over again. However, I also play defensively since I like to use Counter to mess around with people who enjoy running forward and having roll battles (my friend and I tend to have roll battles a fair amount too).
In the context of what could be considered pseudo-spamming, I use Link's Bombs and Arrows to put spacing between me and the enemy when I can. This isn't really to just get quick and cheap hits on anyone though - it provokes them to attack me rather than sit still or run away like chickens.