What should I do if two mods are conflicting but I need both?

For starters, if two mods don’t play well together, there may be a conflict. Is there another update or fix for one of the mods? Modders often issue patches. Check the mod description and comments; someone may have already figured out a solution. Or just ask the creator directly; they may know how to resolve the issue, or might want to because they care about their mod being useful. You may also just have to edit the mods’ files yourself, but that is dangerous unless you know what you’re doing. Can one mod be modified to be compatible with the other? Is it possible that a third mod serves as a kind of glue between them? As a last resort, set up a testing board on your wiki where users can post compatibility issues – others may volunteer solutions. Try various combinations, but always make backups!

Second, see if either mod has any known conflicts documented. If not, contact the mod developers; many are still around and may be able to provide a solution. Third, try running them in a different order. Fourth, use a mod merger to avoid duplicate functionality, or see if one mod can simply copy the other. Either fix should be shared with other players. Don’t stop until the problem is solved.