Currently players who run out of Sparks hit a tough spot. Play easier levels? Sure, but that's boring! They want to practice in T3, even if they lose all their sparks! Go in a party? Sure, but what if people start thinking that you're a liar when you die and say that you're out? Then that poor player doesn't get to do anything. If they play normal mode, it's really rare that they get Sparks at all.
And if they play the next day, they have the same problem.
Suggestion: For each day which you log in, if you have less than 5 Sparks of Life, have Spiral HQ send them free Sparks so that they have 5. (Or use some other number, like 3) Make sure it isn't exploitable and that players can easily get more Sparks than 5. (I.e. don't send the mail if they already have a identical mail from Spiral HQ.)
I know that players who are low could always buy more, but it sucks to have zero and have no means to get more unless you go in the Arcade. (And presumably die...then start at the start...and die again...it would be annoying.)
Before anyone says it: I have 50 Sparks or so and I've never ran out.
Bound or unbound?
And if I have less than 5 SoLs, won't I get about 60 - 100 CE worth of Sparks of Life?