umm if you mean the neutral as in stage wise, it's the time when no one has the upper hand besides his or her options. Outside of neutral, a character is in a different position than the other, whether it be on a platform, offstage, in the air, or on the ledge. Assuming you DON'T have the upper hand in the situation you're in (platform camping or ledge stalling can be good depending on your character, opponent, or lack of other options), you should try to reset it. In some cases this may not be a good idea though, like you shouldn't do something stupid like get up from the ledge when marth is charging his fsmash. Instead, look for ways to safely reset, like invincible ledge dash. If offstage look for ways to get back on stage (or on ledge) safely. This requires examining your options though like side b on stage, air dodge on, side b to ledge, up b over head, up sweet spot, etc. It's very important you work on your recovery and DI angles so you don't end up in a situation or combo longer than you have to be. Learning survival di lets you live longer, both combo di and smash di let you reset to neutral or punish or earlier. For example combo di on say marth's fair can help keep your from getting hit again, but as you probably know, is horrible for living an fsmash. DI is so important because it lets you live and reset to the neutral.
In gf set 2, match 2 of pound 3, mango lives through fox upair as puff because of good sdi, this allows him to get out of a bad situation but still leaves him off stage. Even though M2K has the upper hand, he whiffs a bair out and gets punished with a side b. After this, M2K's best option is to tech in place/tech roll(to help reset to neutral) but he misses it and gets jabbed reset grabbed. At this point, M2K's best option (at least I think) is to DI right, which is what he does. He lands on the ship and gets rested. As you can see, there are some options that are great, but at the same time can be predicted or are not always best. In many cases, you need to watch your opponent and pick the best option you can for your opponent AND the situation. You should look into some guides to see new stategies for getting out of situations (like shield dropping!)
good luck and someone can tell me if im wrong too!