When should we apply for Further Leave to remain. Married

[markyc]

Its a little confusing lol. My wife entered the UK under a Spouse Visa under the 5 year route.
She was given 33 months from date of entry. For some reason I always assumed she would need to apply for FLTR 2.5 years after entry (halfway through the 5 year route). I am confused if this is correct or not or should she apply for FLTR just before the 33rd month. Any advice would be most welcome.

Time line:
BRP Issued 01/03/2017
BRP Valid until 15/12/2019

When do you recommend she applies for FLTR.

Many thanks and great site.

[seagul]

immigration-for-family-members/spouse-v ... 73496.html

[vinny]

Be careful.