While you're free to mix and match your skills as you'd like D2R Items It is recommended to have a plan in place and invest as per the plan. You're only given a certain amount of skill points to allot that means you won't capable of acquiring everything on the tree of skills. Even if you invest a lot of money in a certain skill.
This will determine the other skills you choose due to synergies with other skills, which can be found whenever you hover over a particular skill. For instance, the basic Raise Skeleton skill for Necromancers gets a bonus from Skeleton Mastery and Summon Resist. This makes those essential skills that summoners should choose.
Resurrected comes with a respec option which means you're not completely locked into the choices you make, however there are limitations on it (you'll get some respec chances for free while playing in the future, and subsequent ones require the gathering of certain resources). So, don't anticipate being able freely experiment to the extent as you do in Diablo.
A gameplay element that can make you a little nervous is stamina. Essentially, you can only sprint for a brief amount of time before you run out of energy and being forced to walk. You can alternate between walking and running on your own to D2R Ladder Items Buy preserve stamina and ensure you aren't run out of gas if suddenly have to put some distance between yourself and an adversary.
