[Lynn]

pawn Code:

new UsedCmd[MAX_PLAYERS] = 0;

pawn Code:

public OnPlayerConnect(playerid)
{
    UsedCmd[playerid] = 0;
    return 1;
}

pawn Code:

CMD:cmd(playerid, params[]) 
{
    // Do stuff here
    UsedCmd[playerid]++; // This will increase it +1
}

Then from there, it'd be

pawn Code:

if(UsedCmd[playerid] >= 5) { // Change 5 to the number of your choice.