Best way to manage end term of ongoing loans

Hi Experts,

We would like to track ongoing activity for intercompany loans. As part of the process, there is no clear end date to enter at the time of deal creation for intercompany loans. Let say there are two legal entities- X & Y. X lend money to Y and there is no designated end date to receive money from Y. Whenever funds available Y will give it to X. It can be 1 month or 1 year or 3 years. We calculate interest every month and book accounting entries.

Couple of points to consider-

1. If we give current month/ current year as end of the term, most likely users will forget to update the end term of one month or one year.

2. If i give end date as 31 Dec 9999, system will give run time error for unlimited cash flow generation.

What is the good end term user need to give at the time of deal creation?

Pls suggest.