I've learned to write a vector on one line as for example $(a,b,c)$. This can get very confusing if each component of the vector is an expression of several terms like this: $(a+b,b+c,a+b)$ since the commas get mixed up in the mess of signs.
Adding more parentheses doesn't really help since it gets mixed up with the already written parentheses like $((a+b),(b+c),(a+c))$. It almost doesn't look confusing here, but with more complex expressions, it can look very messy.
What I usually do is to write something like $([a+b], [b+c], [a+c])$ and then add an explanation for what the newly introduced parentheses mean, but I'd rather use a standard notation that doesn't require an explanation.
What are the alternatives that can be used without needing extra explanation?
You can make the parentheses bigger and put white spaces before and after the commas (Hans' comment beat me to it). For example: $$\big( a^2+3b+c~,~b^2-4c+d^2~,~e^a + \sin b + \log c \big)$$is produced with
\big( a^2+3b+c~,~b^2-4c+d^2~,~e^a + \sin b + \log c \big). Here~is an unbreakable space, and you can use\Bigor\Biggas needed.