Low level grottos can be pretty useful. At one point, I had a Shogum map that was only 3 floors and pretty quick to run.
Number of floors is one of the things that helps determine the level of a grotto, so maps with higher levels tend to have more floors.
There's no accolade for keeping lower level grottos, but it's probably good to save even the crummy ones until you really need the space.
Sometimes you'll wind up wanting a low level chest for a rare item, and having to hike down fewer floors and weaker enemies helps with that a lot.
Take it from someone that tossed all their low level maps and then realized they needed the Slime Shield from the rank 3 chest >.>; --- Neither the darkness, nor the light. Merely the shadow, reflection of the darkness cast by the light. Condensed and distilled into unification, nothing and all.
Okay, I just keep one for each level for now as I get them, there is no need for me to hunt for a level 3 map when I have a level 1,2 and 4 right?
Not so much one of each level - you want one of each BOSS. Certain quests will ask you to kill or steal from certain bosses (usually under added conditions). Having a short grotto for each boss helps.
What is this and how do you use it?
Ahh, the Grotto Calculator.
Tab 1 (Predict Next Grotto): Enter your hero's highest level attained in any class, and highest number of revocations in a single class, and the level of the grotto map you are using, and it will tell you the likely "ranks" for your next map, with a short overview of attributes for each rank. It will even include the odds of special enemies showing up.
Tab 2 (Analyze Grotto Name): Enter the name of the grotto you are doing, and it will tell you what to expect from it. If you still have the data for the prediction from the grotto you got it from, click "Include Prediction" to narrow it down further.
Tab 3 (Monsters and Items) - this is the page your link led to: If you know the starting "monster rank" (which monsters appear on the first floor), the number of non-boss floors (choose "auto" if unknown), and the grotto boss (or the third part of its name, if boss is unknown), and its terrain type, you can get an overview of what monsters to expect, and what possible treasures can show up on what floors (with odds for each).
Tab 4 (Search): I haven't used this one so I don't know what it specifically does.
Tab 5 (Report): Can give a printable overview of all the information pertaining to a grotto, based on the same info you would input into the second and third tabs.
Once you get the hang of it, the grotto calculator can be very useful - it can tell you what to expect, in general, without spoiling the mystery of randomosity (grotto calculators that can tell you the exact seed number for a grotto can be MUCH more specific). --- "As the good archmage often admonishes me, I ought not to let my mind wander, as it's too small to go off by itself." -Danilo Thann
This site is really useful for having a grotto mapped out including where each treasure chest is located (especially useful for grottos with lots of floors). Just fill in the name of your grotto and pick the corresponding map (either from how the first floor looks like or where the treasure map is located).