The players themselves might want to keep a single sheet of paper with their relevant numbers - with enough room for change.
I do that with my high-level Bladesinger. Bladesingers are basically Fighters with buff spells, so I have many feats (who can change my statistics) and many spells(who can change my statistics. With just the character sheet I'd have to do complex mathematics with every single attack roll (and I have six attacks per round at times).
Let me explain it a little further:
At the top I have my AC.
First, it's divided into Base
(flat 10, a halfling or other small character would have 11 here. Stuff like deflection bonuses, like a ring of protection, also add to this. You don't lose this part of your AC except under exceptional circumstances), Armor
(everything that comes from Armor or Natural armor. You'll lose that part of your armor class if someone makes a touch attack), and Agility
(the Dexterity Bonus, dodge bonuses you always have. You'll lose that part of your armor class if you're caught flat footed or lose your DEX bonus any other way, such as against an invisible character.). Write the numbers down, below each position, and add them up behind - this is your "Base AC". Beside that, I enlist all things that could add to my AC: If I use cat's grace, my AC will go up, I may use the shield spell, or haste, and I have expertise and can excange attack bonuses for Armor class. I write the Numbers they can give below. In the line beneath that, I then write the stuff I actually have. I add these to the Base-AC and write that at the end of the line, As my AC.
Example:
Code:
Base Armor Agility Base-AC | Dodge Shield Haste Expertise |AC
13 8 7 28 | 1 7 4 (5)
28 | 1 7 0 3 | 39
Then do something similar with your attacks and damage: Write your attacks (if you have more than one) in one line with the normal attack bonus (i.e. Your base attack + Strength + The Weapons's enhancement bonus + 1 For Weapon Focus. The attack bonus you have without any spells, feats that are not always active, or special modifiers.) At the beginning of your turn, you write the actual numbers below that (if changes have occured. This could be spells, and if you have the Power Attack feat, you might want to subtract some of your Attack Bonus and add it to your damage). Also write down the attack bonus you'd have with a single attack (if you must first move to hit your enemy, you won't be able to perform a full attack. Some feats or abilities, like Rapid Shot, give you more attacks in a round, but all the attacks suffer a penalty. You'll probably use those feats most of the time, but if you move, you can attack only once, and this means you won't get that penalty)
Example:
Code:
Attacks:
Single Attack | Several Attacks
+29 |+27/+27/+22/+17/+12
+22 |+20/+20/+15/+10/+05
For damage, write down the base damage you do, and below that the damage you actually do at the moment (There are Spells, feats, and abilities that add to this.)
Example:
Code:
Damage:
1d8 + 14
1d8 + 21
In all these examples, you have the normal values in the uper line, and the actual numbers below. The upper line won't change except your level-up or your ability scores change permanently (i.e. You get a Belt of Giant Strength +4, and your improved Strength Score improves your attacks and damage)
Below that, make a list of all special abilities or buff / protection spells you usually get (I, for example, have learned Haste twice per day and use it for every major encounter. Same goes for the Shield spell.) or you always have (like spider climbing you get from Boots. You mainly write them down to remember you have them.) Beside that, you might want to write down the effect in short (e.g: "Shield: +7 cover to AC" or "Mirror Image: 1d4 + 1 /3 Levels"), and beside that, the duration of the abilities (some are permanent, but most are limited: Haste only lasts one round / level, and boots of speed can be used for 10 rounds per day). At the beginning of the line, you check those abilites that are active at the moment, and at the end, you mark durations (this is mainly for stuff that can be measured in rounds, like 1 Round/level or 1 Minute spells If it's measured in Hours, it will probably outlast the combat, and you need the DM to tell you how much time has past). Permanent abilities get a special sign to show that they're active constantly:
Example:
Code:
P Spider Climbing
P Combat Reflexes (Extra AoO)
X Cat's Grace (1d4+1 Cha): 1 hour/level. +3 Cha
Blur (20% Miss Chance): 1 min/level.
X Mirror Image (1d4+ 1/3 Levels): 1 min/level. 5 Images. x x ||||
Shield (+7 cover AC, 1/2 battlefield): 1 min/level.
X Haste (+4 AC, extra part. Action): 1 round/level. x ||
Below that, you note your Hit Points and Subdual Damage. If you do this on the character sheet, writing down, erasing, writing new, you'll have worked right through it after 10 game sessions.
