Solve et repete - Respect your obligation first, then you can ask for reimbursement. Used in those situations in which one of the two (or more) parties needs to complete his obligation before being allowed to ask for the opposite obligation to be respected by his counter party. Usually this principle is used in fields and subjects in which a certain general steadiness or uniformity of the system has been considered a relevant value by the legislator. The case is typical of service contracts with repeated obligations (like with gas, water, electricity providers and similars), in which irregularities on one side cannot be balanced if not in a regular situation (i.e., of payments) on the other side. The customer, for example, might be asked to pay regularly the new bill, before contesting the previous one in which he found irregular calculations, and asking for a balancement with newer bills; he thus cannot by himself determine a discount in the next payment.⏎
Ubi lex voluit, dixit; ubi noluit, tacuit - When the law wanted to regulate the matter in further detail, it did regulate the matter; when it did not want to regulate the matter in further detail, it remained silent (in the interpretation of a law, an excessively expansive interpretation might perhaps go beyond the intention of the legislator, thus we must adhere to what is in the text of the law and draw no material consequences from the law's silence).⏎
Ultra posse nemo obligatur - "No one is obligated (to do) more than he can." Specifies that one should do what he can to support the community, but since everyone has different levels of ability, it cannot be expected that all will perform the same.⏎
Sic utere tuo ut alienum non laedas - "Use your property so as not to injure that of your neighbours." While an individual is entitled to the use and enjoyment of one's estate, the right is not without limits. Restrictions can give rise to tort actions include trespass, negligence, strict liability, and nuisance.[8]⏎