Some people will accept that their in-laws are going to cause problems in their lives and do not do anything about it. This is a big mistake according to Dr Jonas Laforge MD (website here) For some there is going to be the need to sort out the problems and if there are children involved it is important that they are not caught up in the argument and disagreement.
Some in-laws cannot accept that the child has flown the nest and is living their own life so they act as if they are there a lot of the time. Asking for them to come and carry out the most basic of repairs or do a job that they are really not needed for. If this is a weekly event it may be an idea to suggest a time maybe every fortnight when all of you go round. It will show that you are united with your partner and if they are going to be visiting then so are you. Other than real emergencies there is no need to go running the minute they call.
Research has shown that the majority of the times the tension between the generations is between the mother in law and daughter in law. As there are about 60% of marriages affected it is not a thing that you need to worry that you are going through alone. It could be that the mother feels she is going to lose her son if he is not there all the time, so if you can convince her that she is still important to the family it may lead to her backing down a bit.
If you marry early it may be a bit difficult to assert yourself and at this stage the in-laws can sense weakness and try to set the ground rules themselves. The longer you give them control the harder it will be to take it back and if they still feel in control once you have your own children it could be that they try to interfere here as well.
Just because you miss the opportunity early in life it does not mean that you cannot try again later. The older you are the more life experience you will have so the less chance there is that the in-laws can accuse you of being too young to understand life. The one thing that you should always remember is not to involve your children. They need to have contact with grandparents and don’t need to grow up thinking that there has to be hard feelings with the in-laws.