I normally have a non-trivial percentage of machines that are mostly idle, but consume maintenance resources at the same rate. Can you consider looking at machine activity periodically and either extending the maintenance interval or reducing the demand? I have a few mods that provide machine activity feedback and the performance impact isn't noticeable.

I play marathon with slow start mods (Coal & Steam, AAI Industries and AngelBobs in general) so I probably notice it more - resources are more precious and there are a lot of minor parts to produce.

Another pair of thoughts for this kind of playthrough:
- At times it's annoying to have maintenance events you can't do anything about for hours because the game is so extended. It takes a long time to get to Science 3 and/or lubricants, for example. One thought is to have earlier access to maintenance parts, but those parts are only good for Tier 1 machines (this is what I wanted to add with the hopefully-future mod API; iron-based components and oil from fish).
- Another thing is with larger bases that AngelBobs produces, it is a lot of work to run around and maintain things. I'm not sure what to do about this that doesn't break balance, but a wider network of bots is needed early on for QoL. Balancing maintenance/redundancy in production chains is great but running around a lot not so much. This is actually the bigger issue, I think.

Those are my thoughts so far. Thanks again for the mod!

I fully agree on the "early game grind". To deal with this the recent update introduces a "wear reduction factor" that is applied to all crafting machines that sit idle. By default, this factor is 80%, meaning that idle factories now need only 20% of the maintenance items they needed beforehand. This also reduces the amount of maintenance signs.

To get to know if a machine has been idle the whole time, the current amount of produced items is compared to the amount of items produced last time. Latter value is saved in the maintenance information table for each entity (of type "CraftingMachine"). This means, that labs, miners, boilers, generators and so on are not affected by this.

Regarding the other points you mentioned:
- Tiered maintenance items: I'll think this trough, the mod-api is already on my list.
- For the second point i thought about adding some kind of "maintenance station" that helps with maintenance until bots are available. This is purely script based or a simple small roboport, but again, you're right: I spend hours running around and replacing things, even with personal robots available. Not that much fun.

I really appreciate your suggestions! Thank you :)

Awesome, thank you! Look forward to trying it out.

I like your idea of a script based maintenance station, because it is simple and doesn't grant bots early overall.

BTW, the things I like most about this mod is it gives a real reason to buffer resources (besides hording) and to design for redundancy. Whatever you do, don't change these things :)

Something like this might work well for early maintenance - if the bots are slow, they're not useful for construction but would still be useful for background maintenance. : https://mods.factorio.com/mod/Construction_Drones

i just removed those drones from my current map since i had lots of problems with them, eg blocking the way of vehicles (AAI miners and haulers), and even destroying themselves or the vehicles. they also quite often got lost or stuck in the spaghetti of my factory and couldn't reach their destinations since they can't fly. I'm trying nanobots instead now (no idea whether nanobots work with this mod since i only today have discovered this mod, but why wouldn't they?)

Nanobots didn't work for me; I think they work differently and couldn't apply maintenance. I use this : https://mods.factorio.com/mod/early_construction
They are basically single-use construction robots ( though they can deliver multiple times). Only downside is the mod doesn't have early infrastructure for them, so you need to walk around everywhere.

i found that too (nanobots not working for repairs) :-(

i also had some other problems, eg that i have to guess which items are required for repairs: i only saw the info "filters: 2 <icon of something>, 1 <icon of something else>" ... until i have played this until midgame, i have no idea what those icons stand for and what research i should do next to be able to repair machines as soon as possible.

another problem i got: my game is 2 hours old (and thus most of the few machines are built less than an hour ago) and i use default settings of this mod, yet half my machines already need repair and one even was broken. and those machines even are burner based (3 of 6 smelters need repair and 2 had a breakdown around 30% age, 2 of 3 burner assemblers need repair at age 14%, and 1 of 4 burner labs; probably requiring oil products for some of them). to me this is much too soon and much too much damage for "normal" settings, having no bots, none of the required tools for repairs, and already a third of my machines damaged after less than 1-2 hours of placing them.

if these values are typical and unless i first improve my skills in speedrunning, i probably will have built my factory 3 or 4 times because of missing maintenance, and thus it will take even much longer to advance to batteries, plastics, lubricant, and bots(!) and thus I'll have to rebuild my factory even more times until i can set up some effective maintenance. at least this mod seems to be "incompatible" with other mods that extend gameplay (like longer burner stage, burner labs, etc). YMMV, but I'll restart my map with more difficult chains now and with less time pressure.

In the next version of this mod, a script based "maintenance unit" will be added, which is unlocked after researching steel processing and automation 1. That's because I wasn't able to find a good early game construction mod, too.

This new unit is a simple chest the player can fill with maintenance items which are then automatically distributed to adjacent machines. Provided with repair tools it will repair broken down machines and slowly heal them. I tested this already and it really takes off some of the tedious "running and replacing" in the early stages of the game. The unit needs electricity to work and the player needs to visit it from time to time (like every 2-4 hours) for refilling. This unit is also helpful even if bots are available, as it is independent from logistics networks and therefore especially useful for remote production sites.

Also, i found (and fixed) a calculation error regarding the "bad maintenance ageing malus" which was effectively applied one time too much and resulted in machines ageing 33% too fast. This is probably the reason that the machines are worn out faster than intended.

I thank you all very much for your feedback that helps balancing this mod!