lenght of overseas use

Everything you need to know is written in the terms and conditions and fair use policy.

https://www.idmobile.co.uk/help-and-advice/eu-roaming/fair-usage-policy#before-june-2023

Permanent Roaming.

We understand that sometimes you'll want to roam for a few weeks at a time or take an extended trip. However, it is important to remember that if you spend more time abroad than you do in the UK over a 4-month period, we might think you're permanently Roaming. If you do spend more time abroad than in the UK over a 4-month period, we'll have to take the following actions:

1. First, we'll send you a text reminding you of the fair usage policy. 
2. If you don't change your usage behaviour to comply with our policy, we'll also ask you to provide proof that you do still have strong ties to the UK, like a UK bill or bank statement.
3. If you don't/can't provide any proof of having strong ties to the UK, and you continue to roam more than you use your plan in the UK, we'll have no choice but to apply an additional charge to your EU Roaming usage. 
4. Finally, when this additional charge is applied, we'll send you another text message - to make sure you're aware of the situation, giving you a second chance to stop Roaming to avoid charges. 

The additional charges applied to your plan if you're a permanent roamer that continues to use their allowances abroad are:

• 3.2p per minute per call.
• 1p per text.
• 10p per MB of data.