The main pro of dual citizenship is the ability to live, work, and claim benefits in two different countries. It may, however, make international travel more complex and increase one's tax liability. The details of holding citizenship in two countries vary dramatically depending on the countries involved, and the decision to hold dual citizenship should be made on a case by case basis.
For many, the primary benefit of dual citizenship is the freedom to move between two countries easily. This often means not having to apply for a visa or other permission to enter or leave a country as often as one wishes. It can also simplify the process of purchasing a home or business in either country.
Another pro of holding dual citizenship is being able to work in both countries. Many companies will not accept applicants who do not already have the legal right to work in that country, and obtaining a work visa can be a complex and expensive procedure. Some companies may even prefer candidates with dual citizenship, if they have branches in both countries.
By acquiring citizenship in a country, a person is then eligible for all of the rights and benefits of a citizen of that country. This generally includes voting in elections and receiving state benefits, such as pensions and healthcare. While residency may be a factor in claiming benefits, many people with dual citizenship are eligible to receive all the rights of citizens of both countries for their entire lives.
One of the downsides of dual citizenship is having responsibilities to both countries, which can include taxation and military service. The tax laws for dual citizens vary between countries and are often tied to employment and residency. It is important to consult a tax professional to ensure that all taxes are paid properly.
Holding two passports can make international travel confusing. Often, one must enter and leave a country on the same passport. Immigration officials in one country may not have access to passport data from other countries, and this can lead to problems when traveling.
Many countries do not allow their citizens to hold citizenship in another country. Those that do, may still restrict a citizen from exercising certain rights, or may deny him a passport or access to benefits unless he renounces his citizenship in the other country. Every country has its own immigration laws, and they may change frequently.