Farming for resources is the most time consuming task, and there's nothing more frustrating than getting the latest character and realising you'll need a whole week to bring it up to max level. Farming can also be an occasion to level up the rest of your roster as well, be it by bringing an extra Eddie or two as a tagalong on higher level dungeons, or playing lower level dungeons with new allies. If you go that route, it may not hurt to look at the XP booster packs in the store. Check the options, though, as buying two days singly can be the same as buying 3 days at once. Always check the other options out there before clicking purchase.
The recent game updates changed the ressources you can obtain through farming and the locations where you can find the best options. The evolution of the Sands of Time limit per player (up to 120 at level 100) also changes this paradigm, so our guide will now reflect those.
It is important to note that most 5 wave levels (excluding night city) can be farmed under the minute (per run), but if (when) you can farm lord of flies (single boss wave, last level of night city) you fall under the 30 seconds mark, which greatly speeds up your daily farming routine.