| Orfamay Quest |
The monster creation page lists ability DCs by CR.
They roughly go up by three points every four levels.
That table also lists expected AC by CR. So you can figure out whether you're more likely to hit a critter, or to resist its saves, and make selections appropriately.
| Chess Pwn |
it's also scaled by what you care about.
Fort saves are poisons, statuses like blind or deaf, missing actions and the bulk of instant death effects.
Will saves are lose control of your character, miss actions, and some instant death.
That's why people say pump will a ton because they feel it's penalties for failing are the worse.
| Renegadeshepherd |
When it comes to deciding between dedicating resources to offense or defense in this game go with offense. Aim to get at least a 50/50 chance to defend yourself but the system is based on you killing the enemy as quick as possible. Even the highest of defenses can be beaten by crits or similar auto succeeds.
| Mage of the Wyrmkin |
It really depends on your perspective. I tend to favor defense over offense as the game is a marathon and not a sprint to the finish. Over the course of the adventure your character will be required to make multiple saves and a 50/50 chance will mean that your character is likely to fail quite a few of them. A character that is incapacitated or killed a good percentage of the time is not a fun character to play IMO. I suggest that you devote as much resources as you can to your saving throws (and rerolls)without gimping your character concept.