Pulsating Point Lights?

If you want a continuous loop, it's ideal to use a while loop with some for loops:

while Loop Example

while true do
    wait(2)
end

while Loop Composition

while [Argument] do
    wait[WaitTime]
end

for Loop Example

for i = 1,10 do
    script.Parent.PointLight.Brightness = script.Parent.PointLight.Brightness + .1
    script.Parent.PointLight.Range = script.Parent.PointLight.Range + .1
    wait(.1)
end
-- You can add a `wait()` here to create a pause between the two loops.
for i = 1,10 do
    script.Parent.PointLight.Brightness = script.Parent.PointLight.Brightness - .1
    script.Parent.PointLight.Range = script.Parent.PointLight.Range - .1
    wait(.1)
end

for Loop Composition

for [Variable] = [StartNumber], [EndNumber], [Increment (Default = 1)] do
    wait(WaitTime)              -- Optional for a typical 'for' loop, but ideal if you want a visible transition
end

StartNumber - The first run of the loop

Ex. 3: the loop will start at the 3rd run.

EndNumber - The last run of the loop

Ex. 9: the loop will stop after the 9th run.

Increment - Regular increase of the run of the loop by a given number

Ex. 2: the loop will run by 2s (2, 4, 6...).

while & for Loop Combination Example

while true do
    for i = 1,10 do                 -- Increase in Range/Brightness
        script.Parent.PointLight.Brightness = script.Parent.PointLight.Brightness + .1
        script.Parent.PointLight.Range = script.Parent.PointLight.Range + .1
        wait(.1)
    end
    wait(2)
    for i = 1,10 do                 -- Decrease in Range/Brightness
        script.Parent.PointLight.Brightness = script.Parent.PointLight.Brightness - .1
        script.Parent.PointLight.Range = script.Parent.PointLight.Range - .1
        wait(.1)
    end
    wait(2)
end

The PointLight will increase brightness and range by .1 every .1 seconds. After each property reaches 1, the process will wait for 2 seconds.

The Pointlight will decrease brightness and range by .1 every .1 seconds. After each property reaches 0, the process will wait for 2 seconds and start all over again.