Can I keep US banks account and credit cards?

I've working in the US via the TN visa for almost 10 years.

I wonder if I can keep the US banks account and credit cards etc. after returning to Canada? Will the SSN still valid? I might keep the existing apartment as a vacation home.

Your SSN won't be valid, but the bank doesn't know that and neither does the IRS, it only really matters for employment purposes.

The main thing you need to do is tell the bank you no longer live in the US and ask them for a W-8BEN form so they don't report any interest paid on your account to the IRS.

Bear in mind if you keep the property you will become subject to US capital gains tax on it. I'm assuming you've been filing 1040s and not 1040NR tax returns so when you move your tax home back to Canada (there is a lot of paperwork to do that) you will cease to benefit from the CGT exemption US residents get.

I think the current limit for CGT for non-residents is $32,000 (or rather it's 0% up to that limit), but check if it's a major issue for you. I'm not quite sure how the US works if it you've become non-resident, whether you benefit from the exemption up until the point that you moved or whether you can only claim the non-resident limit at the point you sell it.

good question.
i would agree with the above poster, just make sure you tell your banks.

Can I renew my existing credit cards if the SSN no longer valid?

Yes, because whether it's valid for employment or not isn't relevant to the bank. It's a valid number, it's just not valid for employment anymore. It has to remain valid otherwise you wouldn't be able to claim social security when you become eligible.

Social security number is valid for next ten years so if you return to US after few years on another job, you can still use it.

That's not what the SSA told me, they told me specifically that your SSN expires when your work authorization expires, and the agent at the SSA office types that into the computer when you apply for an SSN so that it expires at the right time. Based on what has happened with the refund cheques, it's pretty clear they do expire.

The whole E-verify system is based around expiring SSNs, it wouldn't work if they were valid for years after the work authorization had expired.