Disadvantage "Load"

GURPS Characters p. B11 suggests limiting disadvantages by total number of points in order to keep the game from becoming a "circus". This is at best a blunt instrument.

Consider a character with IQ 16 [120], Will 10 [-30] and Per 10 [-30] compared to a character with Trickster (12) [-15], On The Edge (12) [-15] and Enemy (League of Evil Super Assassins; Hunter, 9 or less) [-30]. They both have -60 points in disadvantages, but the first character's are figured into their character sheet once and can be forgotten about. While the second character is likely to disrupt nearly every session with suicidal antics and the occasional random ninja attack unrelated to anything actually relevant to the adventure (until these kill them).

Another way to limit disadvantages is by the relative effect it has on the game: its"Load". Taking many low load disadvantages won't cause the problems that a couple high load ones wll, regardless of their point costs.

Causes of Load

A disadvantage's load depends on some of the following factors:

1. Cognitive Attention - Disadvantages that require the player or GM pay attention and know when it applies have higher load than passive disadvantages that always apply.
   
2. Creativity - Requiring the GM or the players to be creative in interpretation causes more load than fixed rote effects.
3. Worldbuilding Required - Disadvantages that introduce new NPCs, factions, religious practices, etc. to the game setting have higher load than ones that use existing elements.
4. Roleplaying- Personality traits and behaviors that require roleplaying have higher load than less dramatic ones.
5. Disruption - Disadvantages that can cause the intended adventure to go sideways or cause the character to act in a way that's significantly upsetting have higher load than those that align with the narrative and party goals.
   
6. Random Occurrence - Random rolls per session or adventure have increased load over predictable traits.
7. Reduced Functionality- Missing or reduced function in key adventuring tasks have higher load than ones with less impact.
8. Risk - Disadvantages that force risky behavior (e.g. All-Out Attacks) have higher load than safer ones.
9. Negative Synergies- Some disadvantages are significantly worse (with no change in point costs) when paired with others (e.g. Bad Temper taken with Berserk) which increases the load.

Quantifying Load 

The following examples are subjective, feel free to make your own determination based on your campaign's needs.

None: These traits carry no load at all. They are all ones that go on the character sheet once, modify something with no or few conditions, always apply and can mostly just be forgotten about. Examples: Appearance, Ham-fisted, Low-TL (with Borrowed Technology at campaign TL), Reduced Attributes or Secondary Characteristics. Incompetence.

Of particular note here is Reduced Basic Speed. The only mechanical difference between Speed 6.25 and Speed 6.00 is that you go before the whole numbered Speed. This "costs" five points but it's worth less than that. This makes this the lowest load disadvantage in the entire game.

Light: Traits that have only one of the factors above at a relatively low level. Examples: Bad Sight (mitigated), Dwarfism (only due to the conditional Shadowing penalty), Disturbing Voice, Stubbornness, most behavioral Quirks 

Medium: Disadvantages with more than one of the above factors at low levels or one at moderate levels. The vast majority of disadvantages fall into this category. Examples: Absent-Mindedness, Bad Back (conditional and reduced function), Callous, Curious, Hard of Hearing, Phobias, 

Heavy: Disadvantage with one of the factors at a high level, or several factors at moderate levels. Examples: Blindness, Berserk, Dependents, Duty, Enemies, One-Arm, Secret, Trickster,

Extra Heavy: Disadvantages with one factor at a very high level or multiple factors at high levels. Examples: Cursed, Murder Addiction, Quadriplegic 

Leveled Disadvantages, Self-Control, Frequency of Appearance, Mitigators etc. can affect the load of a disadvantage, e.g Enemy (The Soviet Union, Hunter, 12 or less) is much higher load than Enemy (Nosy Neighbor Beth McClursky, Watcher, 6 or less). 

Load Limits

In addition to a total negative point limit, you can also consider load when making characters. Taking "Miller's Law"  into account (which suggests that people can hold 5-9 discrete things in short term memory at any time) you might consider allowing the following:

• Any number of no load disadvantages
• No more than seven of Light or more (and remember your five quirks may count here!)
• 2-3 Medium load
• No more than one of Heavy load
• Zero of Extra Heavy Load, unless you are prepared to make this problem a focus of your campaign