The basic set includes vaccines against tetanus and diphtheria, MMR (measles, mumps, and rubella), and polio.
For Hepatitis, I recommend a combination vaccine which also provides life-long protection against Hepatitis B. The WHO's current recommendation advises Hepatitis B vaccines for all children worldwide.
You can check the vaccine recommendations for your destination country from the website of the National Institute for Health and Welfare (THL) if you are in Finland. The most recent recommendations also include a seasonal flu vaccine for all countries, depending on the results of an appropriate risk assessment.
If you belong to a group that is advised to take a flu vaccine in Finland, then I'd also advise you to get one if you are going anywhere abroad. Such groups include, for example, children below three years of age and anyone over 65 years. Also, bear in mind that viruses may be active during different seasons in different areas around the globe.
Boosters as necessary
It could be difficult to assess the existing immunisation status of adults because the information is not necessarily all kept in one place, and therefore it is a good idea to keep your own record of your vaccines. I'd also advise you to obtain the yellow vaccination card recommended by WHO.
If you are unsure about your immunisation status, you should consider taking at least a tetanus booster, as it also protects you from diphtheria. It won't cause you any harm, even if it turns out it wasn't actually needed. Tetanus vaccinations provide protection for 10 years.
An MMR boost is also appropriate if, for instance, you have any doubt an earlier set of vaccinations may not have been complete. It also protects you against measles, cases of which have recently been reported more often than before even in Europe.
If you are travelling far, the necessary immunisation programme should be determined individually. You may need vaccines against yellow fever or typhus, for example. Some countries require a yellow fever vaccination certificate, but usually this rule doesn't apply to passengers coming straight from Finland.
Don't forget that ticks may spread diseases!
In addition to the Finnish archipelago, ticks and mites are a common nuisance in Baltic countries and eastern parts of Central Europe. There is no general vaccine against Lyme disease, but if you are planning to spend a lot of time in nature, you might consider a three-part vaccine against tick-borne encephalitis (TBE).
A month is enough time for the necessary vaccines, even though the recommended timeframe is six months. You should always consider the facts carefully, because some vaccines are simply overmarketed.
For instance, there has been extensive news coverage about cases of drug-resistant tuberculosis in India. In Finland the TB vaccine was excluded from the general vaccine programme in 2006, and, at least for now, is not recommended for the average child traveller.