Do all products support vector printing from Illustrator (AI) files?

[matchaquiet]

Hi everyone,
I’m a designer using Adobe Illustrator and I upload vector (AI) files to Zazzle.

I don’t speak English fluently, so I used AI (artificial intelligence) to help write this post.
I also apologize if this topic has already been discussed—I tried searching the forum, but I may have missed it. Thank you for your understanding!

I’ve read that most products support vector output, but I’m wondering:

1. Are there any specific products that do not print using vector data?

2. If a product rasterizes the artwork, is there a list or a way to tell before publishing?

3. Has anyone noticed unexpected print results from AI uploads on certain items?

I’m asking because I’d love to design efficiently and avoid quality issues.

Thanks in advance for your insights!
– matchaquiet

[matchaquiet]

Here’s one more related question I'd love to clarify:

If I upload one vector (AI) file and apply it to multiple items of different sizes (like 8x10", 16x20", etc.),
will Zazzle automatically resize the vector cleanly for each item?
Or is it better to prepare individual files in the exact print dimensions for each product to ensure print quality?

Thanks again for your help!

[matchaquiet]

I came across a comment in another thread mentioning that Illustrator files retain vector properties when uploaded,
so they can be scaled without losing quality.
It wasn’t an official statement, but I’m hoping to confirm if that’s generally true across products.