Switching to 12/12 instantly or gradually?

I've heard from somewhere that if the switching is made gradually from 18/6 to 12/12, like adding 1 extra dark hour every day, then the plant doesn't stretch that much and you get more dense buds.

Is it true?

i think its a personal preference thing. streatching goes for weeks so i dont know if doing that for 1 week would really help but it might.

I just change instantly

Instant, keep it simple

I veg 18/6 and flower 12/12. No in between. My plants are either in veg or in flower.

I've been experimenting with light cycle manipulation and found if you drop your hours of light gradually it will reduce stretching somewhat but it comes at the cost of a longer veg time. I'm not sure that reducing by one hour a day will help much because it takes time to work...plants don't grow much in one day; but if you reduce by an hour say every week that can make tighter nodes after the flip and arguably more yield; jury still out on that because I have yet to harvest the plants; still flowering out right now. The idea is to mimic the suns natural cycle; you never see stretched out plants outdoors right?
I used to run only the 2 light cycles but when I added an extra veg area for preflower staging I tried this method which btw I read about in Skunk mag; not my idea but it does seem there's something to this: try reducing he light by one hour to 17/7 in the last week before you plan to flip to 12/12..it seems to trigger a response from your plants resulting in tighter nodes up top. I liked the result so much I did it to the next set of plants queued in my perpetual. This time I went a week of 17/7 and another week of 16/8 and took some pics of my cherry bomb both before and after the flip:

As you can see in the before flowering pic there's spaces near the bottom of the plant where maybe I had too many stuffed in my veg tent and got some stretching. At the top though the nodes are nice & tight. In the after pic which is only about 2 weeks into bloom the buds have already begun touching each other resulting in long spires of solid bud.
I don't think you have to reduce by an hour every week all the way down to 12/12 to trigger a response from the plant just reducing by one or 2 hours of light for a couple weeks is enough to give result. Not sure how it would work on full sativas either but don't take my word for it; try it yourself....

24/7 to 12 /12 here

20/4 straight to 12/12 for me. I keep things simple.

im just a lazy fuck dont feel like taking a second and program the timer