[RIDE2DAY]

If the code you're going to execute isn't too heavy you might use a task and loop through the connected players with y_iterate:

PHP Code:

task my_task[500]()
{
    // General code here.
    foreach(new i : Player)
    {
        // Per-player code here.
    }
} 


As an alternative, you might use a ptask, much better in my opinion:

PHP Code:

ptask my_player_task[500](playerid)
{
    // Per-player code here.
} 


Player tasks start to run when players connect while global tasks run always. You can read more about tasks here:
https://sampforum.blast.hk/showthread.php?tid=571044

Anyway, if you're wondering what's better regarding your original question, a timer for each player is the way to go. Take a look to this thread:
https://sampforum.blast.hk/showthread.php?tid=643553