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The quasi-one-dimensional molecular conductors (TMTTF)2X commonly undergo a charge-order transition upon cooling. For tetrahedral anions (X=BF4-, ClO4-, and ReO4-), in addition, anion ordering is observed. In a comprehensive infrared study, we trace the resonance frequencies of the charge-sensitive vibrational modes to determine the charge disproportionation 2δ=ρrich-ρpoor as a function of temperature. In combination with analog investigations for the centrosymmetric anions, we conclude that charge order does not depend on the anion shape and symmetry, but is intrinsic to the TMTTF stack. Since correlation effects are of paramount importance, we find a universal relation between the charge imbalance 2δ and ordering temperatures TCO and gaps ΔCO, respectively. Below TAO the charge disproportionation gradually changes. Ordering of the tetrahedral anions minimizes the electrostatic energy for the anions and organic molecules as a whole, resulting in a 0110 pattern. This way we can understand that deuteration of the methyl end groups enhances TCO but does not affect the anion ordering, which is linked to the anion-sulfur distance. [ABSTRACT FROM AUTHOR]