There are no such things as "suckers."

At this stage of growth probably not, In my opinion they're quite young. I have some maturing plants in the ground that are 7-8 weeks old.As I was picking suckers off , I saw one that looked like a sucker. Only to realize as I was about to pinch it off, it had blooms.

Tomatoes can grow in odd ways, sometimes what looks like a sucker, is really a new shoot off of the main stalk. I'd wait until they're about 12-16" tall. That's when suckers seem to start showing up.

As already said there is no such thing as "suckers". They are simply lateral branches and they will produce fruit. The claim that they "suck" nutrients from the plant - thus the name - has long been proven false and is discussed here often in great detail.

So there is no need to remove them that relates to the health of the plant. Rather it depends on the plant spacing and the method of support used for them.

Pruning/removing lateral branches is strictly optional and will reduce the production of the plant.

The plant in your blue cup is somewhat malformed and the primary growth tip has stunted. That stem second from the left will become your primary stem now. The third stem from the left is just a leaf branch and will replace the damaged one that is on the far right.

Dave

Is there a difference between a "sucker" and a "new shoot off the main stalk"?

Ok wait It will reduce plant production if "suckers" or Lateral stems are prunned? Dang it, wish I read about lateral branches before reading the hype of pruning them!! SOOOO disappointed.... :'(

People do prune for certain purposes as Dave mentioned above-- the use if certain support methods (staking, for example), earlier ripening, larger (but fewer) fruit, allowing extra space for air circulation (when you won't or can't just plant them a bit farther apart) if dampness and lack of air circulation increases the risk of certain diseases at your location.

It is a matter of your own cost and benefit analysis. My own decision is not to prune.

It isn't really hype. No reason for disappointment. Pruning, removing 'suckers', is a choice based on personal experience, methods of growing, length of your growing season, etc.

You have plenty of time to decide what you want to do. I would not just take one opinion.
Your plants need to be much healthier to even consider it. Let them get comfortable in their growing spot, get accustomed to their growing conditions a few weeks.
I do prune some and not others. I like the leaves off the ground. Even with straw mulch.
I prune a bit early, around the two foot age. Let it go for a while and randomly decide depending on my season any given year. (cold climate, altitude, short season)
If growth is slow, i let them go. June can be cold and wet or hot and dry.

Your location, if you plan to use a cage or trellis system, strong supports?, lots or room or small area...healthy soil....

Here is a link that might be useful: should i prune?

Agree that it isn't hype, it is just mis-leading information in many cases and flat wrong in some cases.

Many sites claim it must be done - not just a few "suckers" but all suckers must be removed. Some that you have to do it or the plant will die from lack of nourishment which is amazing since 1000s of plants are grown without any pruning every year. Some claim that you cannot grow tomatoes without doing it. Some even go so far as to claim that you will get much more production from a single stem plant. One source even claims that you must remove all leaves and branches from the plant except for the very top cluster of leaves.

There are almost an unlimited number of previous discussions here about the pro and cons of pruning with many opinions offered. But the one thing they all have in common is that it isn't mandatory and that it depends on your goals and the circumstances. :)

Dave

Once nice thing about "suckers" is that they do root easy. If you want more plants, there you go.

I nipped them (except the ones I missed) when my plants were small, wanting to get them up into the light in my shaded patio. When they got to about 4' I said "go crazy guys."

Strictly for what it's worth, and inline with "spacing" comments above, in my narrow space I might go for more varieties of smaller plants next year. That would mean removing suckers (in common usage of the term) to keep plants narrow. For me, a narrow Sungold next to a narrow Sweet100, is better than making a choice, one or the other.

So far just about 100% good advice, the best of which saying it all depends on how you work, not someone else. if you have the population and the room, why not prune a few and let a few go hog wild and see which pays out the best?

First to address Op's question:
I would say leave them, whatever they are called suckers or branches, until after plant out when the plants are 12" to 18". Then , depending on your choice do whatever you like to do.

ARE THEY SUCKERS?
I personally prefer not to use the name "Sucker". It has a bad connotation, in my opinion, which has nothing to do with if someone wants to remove them or not.

Branching have different forms. Example my 20" RC ML has a "V" branching. Then at the lower nodes I noticed several smaller growths. The latter is different from the former. I don't want those 3 or 4 tiny growths become branches, b'c the top "V" branches each has buds and I give priority to those.

It is also important to know the timeline on new branches. Lets say that we are into 3rd month of our growing season and have about 70 more days left till the end of season. Now we see new growth/branch appearing. Let us just do a simple math here:

It has been studied that from flower to ripe fruit it take 40 to 60 days (depending on variety and fruit size). Let us take 50 days as an average for the sake of simplicity in this example. Now how long more it will take for this new growth/branch to produce flowers ? lets be optimistic that it will take about 30 days. Then it will take another 50 days on top of that (from flower to ripe fruit). So then in the most optimist estimate that new growth/branch will require about 80 days to produce any ripe fruit. Well, we have only 70 more days to go,( Take or leave a week or two.) PLUS in late season both growth and ripening should slow down considerably. SIMPLE MATH !
So even according to the most optimistic view on NOT PRUNING any new growth after certain time line is not going to make any contribution, as far as we, the grower, are concerned. So in this case those branches will just suck up some of the plants energy without being able to pay it back. In this example we did not take into account the amount of energy that the plant takes away from growing fruits to growing branches. According to layman's version of the law of Thermodynamics:
YOU CANNOT GET SOMETHING FOR NOTHING.

OTHER PRUNING CONSIDERATIONs.
Aside from the "SUCKER" issue, there are different growing styles:

-- Caging with ample spacing
-- staking, stringing with tight spacing like greenhouse market /commercial growing.
--- "per square foot" land resource and productivity considerations.
--- Container growing

In the final analysis, either method is optional at best and one can choose whichever she/he wants.

Branches (with leaves) produce energy for the plant, they don't 'suck' it up.

True, but you'll get a better balance of vegetation to root ratio and thereby more production per square foot of space if you plant a little closer and sucker plants. I wouldn't even think of growing over 500 plants in 2800 square ft. without suckering: