NLV visa renewal

I'm sorry I'm a little confused. Have you just arrived in Spain with your NLV and are now looking to use the visa to apply for your 1st TIE? Or have you had your TIE for 12 months and are now wishing to extend it for another 2 years? Your question suggests that you haven't yet picked up your TIE.

AFAIK The financial requirements for the renewal of your TIE will be similar to your first application but you'll need to have twice the funds available as the renewal is for 2 years.

I arrived in Spain last November, had my TIE appointment last month and have a date to pick up my TIE cards on the 18 of next month. 
2 Questions really,

1. when will I need to re-apply

2. My income NOW being from rent of a commercial property and some savings as opposed to purely savings on my original application. How is best to show the rental income? It will be about half rent and half savings. Will bank statements showing rent be sufficient going into my private bank account?

You'll need to renew yout TIE card within one month before the date it expires, to 3 months after it expires. the date is on the TIE itself.

I'm sorry but I can't help you with your funding query as this is based on a personal assesment. However, a lot of people are saying that you need twice the amount because the TIE is valid for 2 years but this doesn't make sense. Why would your yearly income have to double to cover 2 years? I suspect that if you can show that you have similar savings and income to your initial application then there should be no problem.

Your annual income doesn't have to double, but as you're applying for 2-year renewals, for years 2/3 and 3/4, you have to prove that your passive income and/or savings will cover the whole 2-year period each time.