The chances are good that if you get a patent on a successful invention, someone, somewhere will try to violate your rights. This will require enforcement of your patent rights. Patents are also not free. They must be maintained with periodic maintenance Fees.  This section of Ypatent provides helpful links of interest with respect to maintaining and enforcing patent rights. 

Definitions:

Freedom to Operate: refers to a determination that the commercialization of a prodct does not infringe third-part IP rights, in particular patents. Becasue IP rights have a territorial effect and a restricted lifetime only, a FTO analysis does not only focus on the technologies as such, but also considers where IP rights are in force and when they expire. If, in the course of an FTO analysis, IP rights that are likely to be infringed by the commercialization of a given product are detected, one should considr whether or not they are valid and enforceable. If not, respective countermeasures should be considered, like invalidity opinions, oppositions, nullity actions, or post grant review/inter partes review. As an alternative, in-licensing of the respective IP rights could be a solution. Numberous patents can be involved with respect to a product. For example, for ADCs, an FTO anlysis encompasses not only the antibody but also the toxin and linker. Even if a patent has been awarded on a structurally improved second generation antibody, it can still be the subject of ealrier third party patents protecting teh starting antibody, if these are still in force.  (Storz, “Antibody-drug conjugates: Intellectual property considerations” mAbs 7:6, 989-1009, 2015)