Retired solicitor here. In my view everyone should make a will, irrespective of how young they are or how much assets they think they will be leaving, unless they are categorically happy with their estate being distributed under the intestacy rules. Even then, the intestacy rules do not govern certain things, like your wishes as regards your funeral etc.
Please note that the rules vary depending on which jurisdiction you are in, and there are different rules depending on the timing of different events.
A good place to start to find out how the intestacy rules might apply to you is >>>
www.gov.uk/inherits-someone-dies-without-will
It is possible to make a basic will and then later amend or update it as your circumstances change and develop, and indeed there are certain life events (eg marriage) which will revoke an earlier will, so once you have made a will it is a good idea to review it from time to time to make sure you are still happy with it. It is particularly important to review a will after any major life event - eg birth of a child, death of a partner.
As well as making a will, everyone should also consider putting in place powers of attorney which will kick in only if and when something unfortunate happens. None do us know when that something unfortunate might happen, and once it does we may not be in a position to direct how our affairs should be managed and it is an incredibly difficult and stressful additional burden for surviving family and friends to deal with the situation when someone is incapacitated and that person hasn't put in place the mechanisms to allow others to take sometimes very basic steps to keep things going....like dealing with bank accounts, utilities, mortgages etc
A little bit of thinking ahead, and seeing this as being sensible rather than morbid, means you can put your mind at rest that after if you are incapacitated or once you are gone, whatever wishes you have about how things are to be dealt with in those circumstances will (hopefully) be respected.