What you do with your photos is up to you. I process all my keepers to some degree or other. I also shoot raw so I can control how things look, synchronizing white-balance and adjusting sharpening and noise to my tastes.
If you’re shooting JPG and your camera does it’s best to optimize each photo then perhaps you won’t be able to improve on it.
I agree. I think that in order to get the most out of your photos there needs to be some processing with raw. In jpeg mode there doesn't tend to be much you are able to change without making things worse. In raw, white balance, sharpening and maybe some tone curve adjustment to take away from the flat look that sooc raw tends to have.
Just my opinion..
Do all photo's need to be processed?
No. Some photos look good enough without further processing.
How do you know if it needs it or not?
If they don't look so good, then they could probably use a little Lightroom love, or a lot.
Or is it subjective?
To a large extent, yes. But also, sometimes a photo is just severely lacking in contrast, and so black-point (and/or contrast) really needs to be adjusted, and almost all viewers would agree.. (barring artsy considerations as you said..). Likewise, if photo is severely underexposed (or over-exposed).. etc. etc.
Bottom-line: along with subjective considerations, it's a matter of experience - knowing what a photo needs, and how much, and what you can and can't do...
PS - I can almost always improve a photo if I spend enough time with it, but sometimes it's just perfect the way it is - I end up backing out any adjustments I make.. - hard to know ahead of time, especially if you are new to this stuff..
all depends how good the photographer is with camera imo
photos have been edited since the start of photography; even when films were put one hour labs the were 'edited' so it's nothing new
Every photo can be improved with edit but not every needs improving.
Strictly speaking, a Raw file is not an image file, or at least not a color image file. So without at least some minimal processing there can be no picture - it can be the default processing done by the Raw converter or it can be more extensive. Every converter is different, but third party converters like Lightroom tend to be more minimalist in their defaults, thus leaving more room for user input, while converters supplied by camera makers try to provide a more finished looking product off the bat and one that reproduces the processing done by the camera when it creates a jpg.
It's depend on your requirement. If it is for commercial purpose where is will be display on big screen or print in big size, it must my edited for major and minor errors. If it is for normal purpose, you may use cost effective minor editing.
Do all photo's need to be processed? How do you know if it needs it or not? I mean other than if you want to be artsy with your pictures like making HDR effects, etc. Or is it subjective?
Actually all photographs are processed. There is no such thing as an unprocessed photograph. Whether you do it consciously using a raw editor, or let the camera make decisions for you doesn't matter really as you apply an interpretation of the raw data. With film the same thing applies. There the choice of film stick, the filters you use, and the printing technology and dark room decisions are unavoidable "processing" steps. In digital, a scene rendered physically correct as captured by the sensor is very boring and looks nothing like the jpeg out of camera nor like the default Lightroom rendering. This is why SOOC is such silly nonsense. Jpegs are cooked files. The default raw rendering in Lightroom is only one possible interpretation and not necessarily a neutral or unprocessed one (far from). Photography as we know it is always subjective. Mainly because human vision is subjective and very different from how a camera sensor works. There is always a degree of toning, contrast enhancement, etc. going on. The raw editor and tools such as Photoshop just gives you more control over it than having the camera do it for you based on decisions the engineering team for the camera made. You can definitely do extremely good photography by never touching a post processing tool and just using jpegs out of camera. Just don't call it unprocessed. You are however leaving some major creative tools unused that could improve your images substantially. In the end however this is all a creative decision and there is no right answer for everybody.