Will POP on my Mac and IMAP on iphone cause problems?

Hi,
I like to keep local copies of my emails on my mac so I use POP to access my gmail. But I don't need to be storing them on my phone as well. I'm currently using POP on my phone but I'm wondering if I change that to IMAP will it cause any adverse conflicts or problem having the same gmail account accessed by both POP and IMAP.
Thanks in advance for any advice/opinions.
B

mfram said:

If you use IMAP on your Mac, your mail will be cached locally so you might as well use IMAP on both. The nice thing about using IMAP on both is that the same mail state will be saved across both devices. For example, when you read your mail on one device, it will show up as read on the other device.

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Thanks mfram. I'm wary of changing my mac mail to IMAP. I really do need to keep copies of my emails on that machine. Copies I can rely on. How much mail history would be cached locally on my mac? Because I need it all.