Making a copy for yourself of something you already legally have, is allowed under copyright law. (So you can make copies of the DVD for personal use while keeping the original safe from wear, damage or loss)
There are laws like the DMCA that ban you from circumventing copy protection. So if you have to circumvent some copy protection first to copy the DVDs, then you break the DMCA or similar law if such exists in your country. However you don't break the copyright law
About the latter i can only say, that its no one's business what you do with your DVDs within your private territory (i mean, without putting out copies that are illegal under the copyright law). For anyone to find out that you broke the DMCA, you have to either use software that betrays you - which you don't, or it means that somebody physically intruded into your territory or broke into your computer to check on you, which is entirely different level of crime than copying a DVD
Whether it is legal to copy a DVD I don't know, it may well be, but the manufacturers put so much copy protection on them that it is next to impossible without specialist software, which, being Windows, comes at a price

It is also difficult to make backup copies sometimes. We have a couple of Sony HDD recorders for recording programmes off air. They record to an internal hard drive, but there is no DVD or Blu-Ray disc slot to copy them to. There is a USB port into which you can plug an external additional HDD and copy stuff to that, but doing so ties the additional HDD to
that recorder only and it cannot be used on any other device,
even another HDD recorder of the same make and model.
Legal it may be, but it's [censored] difficult
