user137073: In Core-Lightning, the default value for our_to_self_delay is set to 600. How do I change this value?

user101498: In Lightning the to_self_delay parameter is influenced by your peer. When a node opens a channel to yours, they advertise the minimum they are going to accept.
On Core-Lightning you can set the minimum value to request from peers with the watchtime-blocks option. You can learn more about this option in the lightningd-config manpage or at the online documentation. By default this value is set to 144 (1 day).
The value of your own to_self_delay will depend on your peer. The maximum value a Core-Lightning node will accept can be modified using the max-locktime-blocks option (same manpage as above). By default this value is set to 2016 (2 weeks).
Just to emphasize: the default value for the our_to_self_delay on Core-Lightning is not 600. You must have picked this from one of your channels, where your peer requested a minimum to_self_delay of 600. Since this is below the 2016 cap set by default, your Core-Lightning accepted to create a channel with this parameter.

137073: <p>In Core-Lightning, the default value for <code>our_to_self_delay</code> is set to <code>600</code>. How do I change this value?</p>
 101498: <p>In Lightning the <code>to_self_delay</code> parameter is influenced by your peer. When a node opens a channel to yours, they advertise the minimum they are going to accept.</p>
<p>On Core-Lightning you can set the minimum value to request from peers with the <code>watchtime-blocks</code> option. You can learn more about this option in the <code>lightningd-config</code> manpage or at the <a href="https://lightning.readthedocs.io/lightningd-config.5.html" rel="nofollow noreferrer">online documentation</a>. By <a href="https://github.com/ElementsProject/lightning/blob/5b3746172f06c235892e3b1c5fbef50b9a9d8c68/lightningd/options.c#L827-L828" rel="nofollow noreferrer">default this value is set to <code>144</code></a> (1 day).</p>
<p>The value of your own <code>to_self_delay</code> will depend on your peer. The maximum value a Core-Lightning node will accept can be modified using the <code>max-locktime-blocks</code> option (same manpage as above). By <a href="https://github.com/ElementsProject/lightning/blob/5b3746172f06c235892e3b1c5fbef50b9a9d8c68/lightningd/options.c#L830-L832" rel="nofollow noreferrer">default this value is set to <code>2016</code></a> (2 weeks).</p>
<p>Just to emphasize: the default value for the <code>our_to_self_delay</code> on Core-Lightning <em>is not</em> <code>600</code>. You must have picked this from one of your channels, where your peer requested a minimum <code>to_self_delay</code> of <code>600</code>. Since this is below the <code>2016</code> cap set by default, your Core-Lightning accepted to create a channel with this parameter.</p>
