I prefer Placidus, as it makes the most sense to me in regards to my chart. It doesn’t change a whole lot when I use equal, but it does change my Venus and North node position to a place that I don’t really resonate with through my life experience. Both sort of make sense, but the Placidus chart makes more obvious sense to me. 

I know a lot of people who really like equal, and find it the most consistent. 

I think the whole sign chart begins the chart with the sign of your ascendent at zero degrees, and each respective house follows that pattern. So, if you have a 23 degree Sagittarius Rising, your whole sign chart will begin at zero degrees Sagittarius, depicting the ascendent as a mathematical point that occurs later in the first house. I think that’s how it goes, I could be wrong. 

I like looking at my whole sign chart. Some placements make sense, but others not at all. So it’s placidus for me.

What if the a particular house system works for a person during a certain period of their life, and another house system seems to work for a later life cycle.

That's a thought!

I started out with Placidus and it made the most sense for me for many years. It still does. 

However, I started using Equal a few years ago. The differences are minimal and subtle, but have been sufficient to spark new insights and new points of focus that have helped me make significant strides forward, so I have no qualms.

To me, astrology is a tool, a means to an end. I'm flexible about how I use it. 

I'll probably keep using both house systems over the years. 

This just blows my mind again...but if you have experienced this i guess it is true,i find it interesting how certain things,like a perfume just fit or work better to some and some not. God excuse my english,you get the point.

Maybe a house system works the same way like in the cycle of every 7 years when the body chemistry changes.

I think this may have happened with me.

There were some people I knew whose Suns were conjunct my 11th house cusp (in Pisces) in Placidus, which isn't really a strong point in my chart otherwise (closest thing is that it's semisextile my Midheaven and loosely conjunct my Moon). I would just keep drawing people with this placement into my life. However, none of the relationships ever went anywhere in the long run. They all disappeared and the authentic connection couldn't be maintained. Now I no longer draw in these people. Under equal, they are solidly in my 10th house and I can see how they've shaped 10th house matters for me. But they aren't in my authentic "friendship" house, which makes sense.

Another thing is that under Placidus, I have Mars (in Leo) in the 4th house. Under equal, it's in the 3rd, albeit very close to the 4th house cusp. When I was a teenager/young adult, there was definitely enough difficult drama at home for Mars in the 4th to make sense. But once I finally moved out permanently, the energy changed and my relationship with my parents improved. Now I look back on my life today and in the past and Mars in the 3rd makes so much sense. It just needed its own independent space to operate!

So in brief, I think my Placidus chart had validity but it didn't tell the whole story. I could give other examples too but those are some big ones.