newbie question on drain couplings & solids hanging up?

I have a simple arrangement in my bathroom - Lavatory drain feeds / vents directly into main stack on 1st (only) floor. Toilet and tub each feed into main 4" septic drain in crawlspace via 3" and 2" Y's (respectively) and share a 2" vent that ties into main stack in the attic space. Tub ties in downstream of the toilet. Using ABS for all drains.

I was looking at the run of pipe from crawlspace wall out to the tank (perfectly smooth and straight) - can't see any real issue with solids hanging up in there. But then wondering if the Y fittings I'm adding are going to have any real effect on the 'smoothness" of the run - if solids (from the toilet) will still be washing down cleanly over these joints.

In general is there a point where couplings / fittings are more likely to cause material to hang up / clog over time? Is there any kind of rule of thumb or best practice when tying this all together (e.g. does it make sense to connect toilet drain downstream of other fixture drains, so they all help wash down the solids)? Or does any of this even matter?

Appreciate your patience when answering these (possibly dumb) questions

thanks

hang ups

All approved fittings and pipe in any material are designed to let liquids and solids pass freely. As long as you have the correct grade on your piping and use drainage pattern fittings where required you should not have any problems. Also if using plastic pipe, make sure you ream inside and outside of all of your cuts.

Thanks - I'm assuming the grade out to the septic is correct (as installed by contractor) - I will be extra careful with the grade on my runs, and to clean out the ends of the pipe best I can (take off any burrs, etc.) as suggested. Appreciate the feedback and the sanity check.

drains

What are you doing, and why do you have to cut the pipe? Making a connection is usually the EASIEST part of the job and the one where you are least likely to make a mistake. Once that is done, however, the rest of the piping can be confusing for a DIYer to do correctly the first time.

I'm putting in the new toilet - the cuts are just the whatever lengths I'm using to go from toilet across to (new) septic in my crawlspace. I'm basically doing the small bathroom myself (except septic - previously installed by local contractor). I just noticed as I was looking at that "smooth" drain run from the crawl out to the tank and wondered about anything hanging up on the joints where I put these fittings.

like I said, probably a dumb question - appreciate the replies.